Ann.
Acad.
Rom.
Sci.
Ser.
Math.
Appl.
ISSN
2066-6594
Vol.
18,
No.
4/2026
CONSISTENCY
OF
PORTFOLIO
ALLOCATION
STRATEGIES
ACROSS
INDEPENDENT
ASSET
UNIVERSES:
EVIDENCE
FROM
DJIA
BACKTESTING
∗
Nazish
Shahid
†
Jiawei
Guo
‡
Haoyang
Liu
§
DOI 10.56082/annalsarscimath.2026.4.305
Abstract
To
determine
whether
portfolio
strategy
outcomes
are
dataset-de-
pendent
or
reflect
broader
trends,
this
study
examines
two
distinct
as-
set
sets.
We
evaluate
five
allocation
models—Equal
Weighting,
Maxi-
mum
Sharpe
Ratio,
Inverse
Variance,
Markowitz
Mean-Variance,
and
Robust
Optimization—using
two
15-stock
groups
derived
from
the
Dow
Jones
Industrial
Average.
Strategy
effectiveness
is
measured
through
a
standardized
backtest
incorporating
a
40-day
warm-up
win-
dow
and
regular
rebalancing
schedules.
Evaluation
criteria
include
historical
returns,
risk
metrics,
turnover
frequency,
drawdowns,
and
execution
fees.
Rather
than
relying
on
a
single
backtest,
this
work
specifically
tests
whether
strategic
performance
remains
uniform
across
∗
Accepted
for
publication
on
October
08,
2026
†
nazishshahid@fccollege.edu.pk
,
Department
of
Mathematics,
Forman
Chris-
tian
College
(A
Chartered
University),
Lahore,
Pakistan;
School
of
Statistics
and
Data
Science,
Capital
University
of
Economics
and
Business,
Beijing,
China;
nazishshahid@arizona.edu
,
Department
of
Mathematics,
The
University
of
Arizona,
Tucson,
United
States
‡
32023230041@cueb.edu.cn
,
School
of
Statistics
and
Data
Science,
Capital
University
of
Economics
and
Business,
Beijing,
China
§
32023230067@cueb.edu.cn
,
School
of
Statistics
and
Data
Science,
Capital
University
of
Economics
and
Business,
Beijing,
China
305
Consistency
of
portfolio
allocation
strategies
306
different
asset
pools.
The
findings
demonstrate
broad
structural
con-
sistency
across
both
tested
groups,
though
localized
shifts
occur
in
sec-
ondary
strategy
return
rankings.
Although
the
Equal
Weighted
model
produces
the
top
cumulative
return,
the
Inverse
Variance
approach
re-
liably
delivers
superior
downside
protection
by
minimizing
volatility,
curtailing
drawdowns,
and
maintaining
steady
position
weights.
Con-
versely,
optimization-driven
techniques
incur
greater
rebalancing
ac-
tivity
and
transaction
expenses
without
yielding
better
out-of-sample
performance.
These
results
indicate
that
risk-focused,
resilient
alloca-
tion
frameworks
offer
more
dependable
portfolio
behavior
than
models
dependent
on
historical
return
forecasts.
Keywords:
portfolio
allocation,
backtesting,
portfolio
optimization,
equal
weighting,
inverse
variance
strategy,
maximum
Sharpe
ratio,
robust
optimization,
risk
management,
diversification,
Dow
Jones
Industrial
Aver-
age
(DJIA).
MSC:
91G10,
90C90,
62P05.
1
Introduction
Portfolio
allocation
is
one
of
the
most
widely
studied
problems
in
finance
because
investment
performance
depends
not
only
on
the
selection
of
as-
sets
but
also
on
how
capital
is
distributed
among
them.
The
foundations
of
modern
portfolio
theory
were
established
by
Markowitz
[
10
],
who
formalized
the
trade-off
between
expected
return
and
risk
through
mean-variance
opti-
mization.
Subsequent
developments
by
Sharpe
[
20
,
21
]
extended
the
analysis
of
risk-adjusted
performance
and
provided
a
theoretical
framework
linking
expected
returns
to
systematic
risk.
These
contributions
continue
to
serve
as
the
foundation
for
modern
portfolio
construction
methods.
Over
time,
portfolio
allocation
research
has
expanded
far
beyond
the
original
mean-variance
framework.
Important
developments
include
im-
proved
covariance
estimation
techniques,
robust
optimization
models,
diver-
sification-based
allocation
methods,
and
Bayesian
approaches
that
incorpo-
rate
investor
views
into
the
asset
allocation
process
[
1
,
5
,
7
,
8
].
More
recently,
comprehensive
reviews
of
portfolio
optimization
have
documented
the
evo-
lution
of
the
field
from
classical
financial
models
toward
more
sophisticated
approaches
that
consider
multiple
objectives,
uncertainty,
and
practical
im-
plementation
constraints
[
16
,
17
].
Despite
their
theoretical
appeal,
optimization-based
portfolio
models
re-
main
highly
sensitive
to
estimation
error.
The
quality
of
portfolio
alloca-
tions
depends
heavily
on
expected
return
and
covariance
estimates,
which
N.
Shahid,
J.
Guo,
H.
Liu
307
are
inevitably
subject
to
uncertainty.
Michaud
[
14
]
argued
that
optimized
portfolios
often
exhibit
instability
due
to
estimation
error,
while
DeMiguel
et
al.
[
4
]
demonstrated
that
simple
diversification
rules
can
frequently
outper-
form
complex
optimized
portfolios
in
out-of-sample
settings.
These
findings
have
raised
important
questions
regarding
whether
the
additional
complex-
ity
of
optimization
models
consistently
translates
into
superior
realized
in-
vestment
performance.
As
a
consequence,
simple
diversification
methods
have
received
increas-
ing
attention
in
both
academic
and
practical
portfolio
management.
Equal-
weighted
portfolios
avoid
estimation
error
entirely
and
provide
broad
diver-
sification
across
securities.
Previous
research
has
shown
that
equal
weight-
ing
often
performs
competitively
relative
to
more
sophisticated
optimization
techniques
[
4
,
15
].
Similarly,
diversification
and
risk-allocation
studies
have
shown
that
portfolio
performance
can
often
be
improved
by
focusing
on
risk
distribution
rather
than
return
forecasting
[
3
,
9
,
13
].
These
approaches
have
become
increasingly
attractive
because
of
their
transparency,
simplicity,
and
implementation
stability.
Among
risk-based
approaches,
inverse
variance
and
related
risk-parity
strategies
allocate
capital
according
to
asset
risk
characteristics
rather
than
expected
returns.
Such
methods
seek
to
reduce
exposure
to
highly
volatile
assets
while
maintaining
diversification
benefits.
Research
on
risk-based
portfolio
construction
has
shown
that
these
approaches
can
improve
downside-
risk
control
and
achieve
attractive
risk-adjusted
performance,
particularly
when
return
forecasts
are
unreliable
[
3
,
9
].
In
many
practical
settings,
port-
folios
constructed
using
simple
risk
measures
have
exhibited
performance
that
is
comparable
to,
or
better
than,
portfolios
derived
from
more
complex
optimization
procedures.
To
address
the
limitations
of
classical
optimization,
robust
portfolio
opti-
mization
methods
have
been
developed
to
explicitly
account
for
uncertainty
in
model
parameters.
Rather
than
relying
on
a
single
point
estimate
of
expected
returns,
robust
approaches
seek
allocations
that
remain
effective
under
a
range
of
plausible
market
conditions
[
5
].
Recent
studies
continue
to
demonstrate
that
robust
optimization
can
improve
allocation
stability,
mit-
igate
estimation
risk,
and
produce
stronger
out-of-sample
performance.
Ex-
amples
include
distributionally
robust
optimization
frameworks,
robust
re-
turn
prediction
models,
sparse
robust
portfolio
selection
approaches,
and
hy-
brid
optimization
techniques
that
combine
robustness
with
decision-making
algorithms
[
6
,
23
–
25
].
The
rapid
growth
of
computational
finance
has
further
expanded
port-
folio
optimization
research.
Modern
studies
increasingly
employ
machine
Consistency
of
portfolio
allocation
strategies
308
learning,
artificial
intelligence,
and
reinforcement
learning
techniques
to
sup-
port
dynamic
asset
allocation
decisions
[
2
,
22
].
While
these
methods
offer
new
opportunities
for
portfolio
construction,
recent
literature
reviews
indi-
cate
that
issues
of
robustness,
diversification,
transparency,
and
implemen-
tation
costs
remain
central
considerations
in
practical
investment
manage-
ment
[
16
,
17
,
22
].
Interestingly,
many
empirical
studies
continue
to
report
that
simple
allocation
strategies
remain
highly
competitive
despite
advances
in
optimization
technology
[
15
].
Recent
work
has
also
highlighted
the
importance
of
understanding
asset
risk
characteristics
before
portfolio
construction.
In
[
18
],
a
volatility-based
analysis
of
KSE-30
equities
was
conducted
using
a
one-factor
credit
cop-
ula
framework
and
portfolio
optimization
techniques.
The
study
showed
that
highly
volatile
assets
tended
to
be
excluded
from
optimized
portfo-
lios,
whereas
assets
with
moderate
volatility
contributed
more
significantly
to
final
allocations.
In
[
19
],
portfolio
optimization
was
investigated
using
the
Black-Litterman
framework
for
the
Pakistan
Stock
Exchange
KSE-30
index.
By
combining
market
equilibrium
returns
with
analysts’
views,
the
study
demonstrated
how
forward-looking
information
can
substantially
alter
portfolio
composition
and
asset
selection
decisions.
While
[
18
]
and
[
19
]
examined
optimized
portfolio
composition–demons
trating
that
highly
volatile
assets
are
systematically
excluded
and
showing
how
forward-looking
methods
can
recalibrate
diversified
allocations—both
studies
relied
exclusively
on
expected-return-based
optimization.
Conse-
quently,
they
lacked
a
comprehensive
performance
evaluation
and
did
not
offer
a
direct
comparison
between
expected-return
optimization
and
explicit
risk-based
weighting
schemes.
Although
substantial
research
exists
on
portfolio
optimization
and
port-
folio
allocation,
the
majority
of
comparative
studies
evaluate
competing
strategies
within
a
single
investment
universe.
Whether
considering
clas-
sical
mean-variance
optimization,
equal
weighting,
risk-parity
methods,
ro-
bust
optimization,
or
modern
artificial
intelligence
approaches,
conclusions
are
often
drawn
from
a
single
set
of
assets
and
a
single
portfolio
experiment.
Consequently,
it
becomes
difficult
to
determine
whether
observed
perfor-
mance
differences
reflect
genuine
characteristics
of
the
allocation
method
or
whether
they
are
largely
driven
by
the
particular
securities
selected
for
analysis.
A
strategy
that
performs
well
in
one
portfolio
universe
may
not
necessarily
exhibit
similar
performance
when
applied
to
a
different
set
of
assets.
The
present
study
addresses
this
limitation
by
comparing
five
portfo-
lio
allocation
strategies,
namely
Equal
Weighted,
Maximum
Sharpe
Ratio,
N.
Shahid,
J.
Guo,
H.
Liu
309
Inverse
Variance,
Markowitz
Mean-Variance
Optimization,
and
Robust
Op-
timization,
across
two
independent
asset
universes
constructed
from
Dow
Jones
Industrial
Average
(DJIA)
constituents.
Using
a
unified
backtest-
ing
framework,
portfolio
performance
is
evaluated
through
realized
return,
volatility,
drawdown,
turnover,
and
transaction-cost
measures.
Unlike
many
previous
studies
that
rely
on
a
single
investment
universe,
the
current
re-
search
focuses
on
the
consistency
of
strategy
behaviour
across
two
indepen-
dent
asset
universes.
The
study
therefore
provides
evidence
on
the
robust-
ness
of
strategy
rankings
and
offers
practical
insight
into
which
portfolio
allocation
methods
provide
the
most
reliable
balance
between
return
gener-
ation,
risk
control,
diversification,
and
allocation
stability.
Throughout
this
paper,
we
use
the
term
consistency
to
refer
specifically
to
the
preservation
of
the
relative
ranking
of
strategies
on
a
given
performance
criterion—return,
volatility,
drawdown,
or
turnover—across
the
two
independent
asset
uni-
verses,
rather
than
to
the
numerical
stability
of
the
criterion
values
them-
selves.
2
Materials
and
Methods
2.1
Dataset
and
asset
universes
The
performance
of
investment
strategies
is
evaluated
and
compared
using
historical
data
through
backtesting.
In
this
study,
one
year
of
asset
price
data
from
the
Dow
Jones
Industrial
Average
(DJIA)
market
is
considered.
Specifically,
we
analyze
the
daily
closing
prices
of
the
following
DJIA
con-
stituent
assets
to
examine
the
performance
of
different
investment
strategies:
Apple
(AAPL),
Amgen
(AMGN),
Amazon
(AMZN),
American
Express
(AXP),
Boeing
(BA),
Caterpillar
(CAT),
Salesforce
(CRM),
Cisco
(CSCO),
Chevron
(CVX),
Walt
Disney
(DIS),
Goldman
Sachs
(GS),
Home
Depot
(HD),
Honeywell
International
(HON),
Johnson
&
Johnson
(JNJ),
Interna-
tional
Business
Machines
(IBM),
JPMorgan
(JPM),
Coca-Cola
(KO),
Mc-
Donald’s
(MCD),
3M
(MMM),
Merck
(MRK),
Microsoft
(MSFT),
NIKE
(NKE),
NVIDIA
(NVDA),
Procter
&
Gamble
(PG),
Travelers
(TRV),
Unit-
edHealth
(UNH),
Visa
(V),
Sherwin-Williams
(SHW),
Verizon
(VZ),
and
Walmart
(WMT).
The
dataset
comprises
the
DJIA
index
and
252
trading
days
of
daily
closing
prices
for
these
constituent
assets.
The
comparison
of
investment
strategies
is
conducted
separately
on
two
subsets
of
assets:
the
first
15
and
the
last
15
asset
price
series.
This
split
is
based
purely
on
ticker
order
among
the
30
DJIA
constituents
and
is
not
Consistency
of
portfolio
allocation
strategies
310
stratified
by
sector
or
market
capitalization;
consequently,
the
two
subsets
may
differ
somewhat
in
sector
composition,
which
can
influence
covariance
structure
and
the
behavior
of
variance-based
strategies.
The
analysis
based
on
the
assets
AAPL,
AMGN,
AMZN,
AXP,
BA,
CAT,
CRM,
CSCO,
CVX,
DIS,
GS,
HD,
HON,
IBM,
and
JNJ
is
referred
to
as
Analysis
A
.
The
analysis
based
on
the
assets
JPM,
KO,
MCD,
MMM,
MRK,
MSFT,
NKE,
NVDA,
PG,
SHW,
TRV,
UNH,
V,
VZ,
and
WMT
is
referred
to
as
Analysis
B
.
2.2
Portfolio
allocation
strategies
In
this
study,
five
distinct
investment
strategies
are
examined.
Each
strategy
determines
portfolio
weights
according
to
a
specific
allocation
rule,
enabling
a
comparative
analysis
of
their
performance
under
a
common
backtesting
framework.
Within
this
framework,
each
strategy
is
evaluated
at
predeter-
mined
points
in
time,
where
it
is
allowed
to
update
its
portfolio
composition
using
information
derived
from
recent
market
data.
This
study
evaluates
five
portfolio
allocation
strategies
that
translate
historical
information
on
asset
prices
into
portfolio
weights
under
a
uni-
fied
backtesting
framework.
Let
N
denote
the
number
of
assets,
and
let
ω
=
(
ω
1
,
ω
2
,
.
.
.
,
ω
N
)
represent
the
vector
of
portfolio
weights,
where
ω
i
denotes
the
fraction
of
total
capital
allocated
to
asset
i
.
All
strategies
satisfy
the
full-investment
constraint
N
i
=1
ω
i
=
1
and
impose
non-negativity
con-
straints
to
prohibit
short
selling.
These
full-investment
and
non-negativity
(long-only)
constraints
are
enforced
uniformly
across
all
five
strategies
con-
sidered
in
this
study—including
the
Maximum
Sharpe
Ratio
and
Markowitz
Mean-Variance
strategies—even
though
these
two
formulations
are
some-
times
implemented
with
short
selling
permitted
in
the
broader
literature;
no
short
positions
were
allowed
in
any
of
the
backtests
reported
here.
2.2.1
Equal-weighted
strategy
The
equal-weighted
strategy
allocates
capital
uniformly
across
all
assets
in
the
investment
universe.
Each
asset
receives
the
same
weight,
independent
of
its
expected
return
or
risk
characteristics.
Formally,
the
portfolio
weights
are
defined
as
[
11
,
12
]
ω
i
=
1
N
,
i
=
1
,
.
.
.
,
N.
(1)
This
strategy
serves
as
a
simple
benchmark,
as
it
avoids
estimation
error
and
does
not
rely
on
model-based
assumptions
regarding
asset
behaviour.
N.
Shahid,
J.
Guo,
H.
Liu
311
2.2.2
Maximum
Sharpe
ratio
strategy
The
maximum
Sharpe
ratio
strategy
constructs
a
portfolio
by
explicitly
opti-
mizing
risk-adjusted
performance.
The
Sharpe
ratio
measures
the
expected
excess
portfolio
return
per
unit
of
total
risk,
where
risk
is
quantified
by
the
standard
deviation
of
portfolio
returns.
Let
r
denote
the
vector
of
expected
asset
returns
and
Q
denote
the
covariance
matrix
of
asset
returns
estimated
from
historical
data.
The
portfolio
weights
are
obtained
by
solving
the
op-
timization
problem
[
12
]
ω
SR
=
arg
max
ω
r
ω
ω
Q
ω
(2)
subject
to
the
constraints
ω
≥
0
and
N
i
=1
ω
i
=
1,
and
upper
bounds
on
individual
weights
to
prevent
excessive
concentration
in
a
single
asset.
This
formulation
selects
the
portfolio
that
lies
on
the
efficient
frontier
with
the
highest
slope
when
measured
relative
to
the
risk-free
asset.
In
practice,
the
strategy
emphasizes
assets
with
high
expected
returns
rela-
tive
to
their
contribution
to
overall
portfolio
volatility.
While
theoretically
appealing,
the
maximum
Sharpe
ratio
solution
is
known
to
be
sensitive
to
estimation
error,
especially
in
expected
returns,
which
may
lead
to
unstable
or
highly
concentrated
allocations
when
implemented
using
finite
samples.
2.2.3
Inverse
variance
strategy
The
inverse
variance
strategy
determines
asset
weights
using
individual
risk
measures
rather
than
expected
returns.
Let
σ
ii
denote
the
variance
of
as-
set
i
,
corresponding
to
the
diagonal
elements
of
the
covariance
matrix
Q
.
Portfolio
weights
are
assigned
inversely
proportional
to
these
variances
and
normalized
to
satisfy
the
budget
constraint
[
12
]
ω
i
=
σ
−
1
ii
N
j
=1
σ
−
1
jj
,
i
=
1
,
.
.
.
,
N.
(3)
By
emphasizing
relatively
low-variance
assets
and
ignoring
cross-asset
co-
variances,
this
approach
produces
portfolios
that
favour
stability
and
are
less
sensitive
to
estimation
noise
in
expected
returns.
2.2.4
Markowitz
mean–variance
optimization
strategy
The
Markowitz
mean–variance
strategy
formalizes
portfolio
allocation
as
a
trade-off
between
expected
return
and
risk.
Instead
of
maximizing
a
ratio,
Consistency
of
portfolio
allocation
strategies
312
this
approach
maximizes
a
quadratic
objective
function
in
which
expected
portfolio
return
is
reduced
by
a
penalty
proportional
to
portfolio
variance.
Using
the
same
notation
for
expected
returns
and
covariance,
the
optimiza-
tion
problem
is
given
by
[
12
]
ω
MV
=
arg
max
ω
r
ω
−
λ
ω
Q
ω
,
(4)
subject
to
non-negativity
and
full-investment
constraints.
The
parameter
λ
>
0
represents
the
investor’s
degree
of
risk
aversion.
Larger
values
of
λ
place
greater
emphasis
on
variance
reduction,
leading
to
more
conservative
portfolios,
while
smaller
values
allow
higher
exposure
to
risky
assets
in
pursuit
of
increased
expected
return.
Unlike
the
max-
imum
Sharpe
ratio
strategy,
which
produces
a
single
tangency
portfolio,
the
Markowitz
framework
generates
a
family
of
optimal
portfolios
along
the
efficient
frontier,
each
corresponding
to
a
different
level
of
risk
tolerance.
Although
mean–variance
optimization
provides
a
foundational
frame-
work
for
portfolio
construction,
its
effectiveness
depends
critically
on
the
quality
of
the
estimated
input
parameters.
In
particular,
inaccuracies
in
ex-
pected
return
estimates
can
significantly
affect
the
resulting
optimal
weights,
motivating
the
consideration
of
alternative
methods
that
incorporate
robust-
ness
to
estimation
uncertainty.
2.2.5
Robust
optimization
with
uncertain
expected
returns
The
robust
optimization
strategy
extends
the
mean–variance
framework
by
explicitly
accounting
for
uncertainty
in
expected
returns.
Rather
than
as-
suming
that
the
expected
return
vector
is
known
exactly,
it
is
assumed
to
lie
within
a
predefined
uncertainty
set
centered
around
a
nominal
estimate
r
0
.
In
this
formulation,
portfolio
weights
are
selected
to
maximize
perfor-
mance
under
the
least
favourable
realization
of
expected
returns
within
the
uncertainty
set
[
12
]
max
ω
min
r
∈S
(
r
0
)
r
ω
−
λ
ω
Q
ω
.
(5)
In
this
study,
the
uncertainty
set
S
(
r
0
)
is
specified
as
an
ellipsoid
char-
acterized
by
an
uncertainty-aversion
parameter
κ
and
a
matrix
capturing
estimation
error
in
expected
returns
[
12
]
S
(
r
0
)
=
r
:
(
r
−
r
0
)
Σ
−
1
r
(
r
−
r
0
)
≤
κ
2
.
(6)
N.
Shahid,
J.
Guo,
H.
Liu
313
This
formulation
leads
to
a
robust
counterpart
of
the
Markowitz
optimiza-
tion
problem,
in
which
an
additional
penalty
term
is
introduced
to
control
sensitivity
to
return
uncertainty.
The
resulting
allocations
aim
to
improve
stability
and
performance
robustness
when
return
estimates
are
imprecise.
2.3
Analysis
A
For
this
part
of
the
analysis,
the
closing
prices
of
AAPL,
AMGN,
AMZN,
AXP,
BA,
CAT,
CRM,
CSCO,
CVX,
DIS,
GS,
HD,
HON,
IBM,
and
JNJ
are
used
to
compute
the
portfolio
weights
corresponding
to
different
investment
strategies.
2.3.1
Backtesting
framework
and
strategy
implementation
The
portfolio
strategies
considered
in
this
study
are
dynamic,
meaning
that
portfolio
weights
are
periodically
revised
as
new
market
information
becomes
available.
At
each
rebalancing
date,
the
existing
portfolio
composition
is
compared
with
the
allocation
suggested
by
the
strategy’s
decision
rule,
and
the
portfolio
is
adjusted
accordingly.
This
process
allows
the
strategies
to
respond
to
changing
market
conditions
while
maintaining
practical
invest-
ment
constraints
such
as
full
capital
allocation
and
the
absence
of
short
selling.
By
distinguishing
changes
caused
by
market
movements
from
those
resulting
from
deliberate
reallocation
decisions,
the
framework
provides
a
realistic
setting
for
evaluating
portfolio
performance
over
time.
Before
the
evaluation
period
begins,
an
initial
calibration
stage
is
re-
quired
to
place
each
strategy
in
a
meaningful
starting
state.
Without
this
step,
portfolios
would
start
fully
in
cash
and
remain
uninvested
until
the
first
scheduled
rebalancing
date,
which
could
distort
early
performance
re-
sults.
To
address
this
issue,
the
first
40
trading
days
of
historical
price
data
are
used
as
a
warm-up
period.
During
this
stage,
each
strategy
estimates
the
quantities
needed
for
portfolio
construction,
including
return
and
risk
measures.
The
resulting
allocations
approximate
the
positions
the
strate-
gies
would
have
held
had
they
already
been
operating
before
the
start
of
the
evaluation
window.
To
illustrate
the
effect
of
this
initialization
process
and
to
highlight
differ-
ences
in
initial
capital
allocation
(Assets
A)
across
strategies,
Fig.
1
reports
the
portfolio
weights
obtained
at
the
end
of
the
40-day
warm-up
period.
Although
all
strategies
use
the
same
historical
price
data,
they
produce
dif-
ferent
starting
allocations
because
of
their
distinct
allocation
rules.
The
equal-weighted
strategy
distributes
capital
evenly
across
all
assets,
whereas
Consistency
of
portfolio
allocation
strategies
314
Figure
1:
Initial
portfolio
weights
(Assets
A)
after
the
40-day
warm-up
period
the
remaining
strategies
allocate
capital
according
to
their
individual
ob-
jectives.
The
inverse
variance
strategy
places
greater
weight
on
assets
with
relatively
lower
estimated
risk,
such
as
JNJ,
CSCO,
and
AAPL,
while
the
optimization-based
strategies
produce
more
concentrated
allocations
based
on
their
optimization
criteria.
These
weights
represent
the
initial
port-
folio
positions
used
at
the
start
of
the
backtest
and
should
be
viewed
as
calibration-based
starting
allocations
rather
than
indicators
of
future
per-
formance.
After
the
warm-up
period,
the
backtest
is
performed
using
the
remaining
data.
Portfolio
allocations
are
updated
at
discrete
rebalancing
dates
rather
than
continuously,
reflecting
common
portfolio
management
practice.
In
this
study,
portfolios
are
rebalanced
every
21
trading
days,
approximately
corre-
sponding
to
a
monthly
adjustment
cycle.
Allocation
decisions
are
based
on
a
rolling
look-back
window
of
recent
historical
data,
allowing
the
strategies
to
adapt
to
changing
market
conditions
while
avoiding
reliance
on
outdated
information.
All
strategies
are
evaluated
within
a
unified
backtesting
framework
that
applies
the
same
market
data,
rebalancing
schedule,
and
performance
crite-
N.
Shahid,
J.
Guo,
H.
Liu
315
ria
to
every
strategy.
To
ensure
meaningful
comparisons,
the
initial
portfo-
lio
value
and
risk-free
rate
are
specified
at
the
framework
level
and
remain
identical
across
all
simulations.
The
annualized
risk-free
rate
is
adjusted
internally
to
match
the
daily
frequency
of
the
asset
price
series.
By
stan-
dardizing
these
settings,
any
differences
in
performance
can
be
attributed
to
the
allocation
methodology
rather
than
implementation
choices.
The
simulation
begins
only
after
the
warm-up
period
has
been
completed
so
that
every
portfolio
decision
is
based
solely
on
information
available
at
the
time
it
is
made.
This
prevents
look-ahead
bias
and
ensures
that
the
reported
results
reflect
realistic
investment
conditions.
Throughout
the
evaluation
pe-
riod,
the
framework
records
portfolio
values,
asset
holdings,
realized
returns,
turnover,
drawdowns,
and
trading
costs.
These
outputs
provide
the
basis
for
the
subsequent
comparison
of
portfolio
performance
across
the
competing
investment
strategies.
2.3.2
Evaluation
of
backtest
performance
outcomes
(Assets
A)
Following
backtest
execution,
Table
1
outlines
the
empirical
performance
of
each
portfolio
strategy
across
risk,
return,
and
transaction
metrics.
Properly
evaluating
these
outcomes
requires
accounting
for
the
strictly
out-of-sample
nature
of
the
decision
process,
as
portfolio
weights
were
computed
using
only
historical
data
available
at
each
rebalance
date.
For
example,
the
Maximum
Sharpe
Ratio
approach
selects
weights
that
maximize
historical
risk-adjusted
returns
over
the
preceding
look-back
window.
Once
fixed,
these
weights
are
evaluated
against
subsequent,
unobserved
price
trajectories.
Consequently,
allocations
optimized
on
historical
windows
can
underperform
during
sub-
sequent
periods.
This
in-sample
optimization
drag
is
reflected
in
the
lower
realized
returns
and
Sharpe
ratios
of
the
Maximum
Sharpe
Ratio
strategy,
reinforcing
that
optimized
historical
performance
does
not
ensure
superior
out-of-sample
results.
Table
1
compares
the
performance
of
the
five
portfolio
strategies
across
return,
risk,
and
trading
characteristics.
In
terms
of
return,
the
Equal-
Weighted
strategy
achieves
the
highest
total
(0.15462)
and
average
return
(0.00075),
followed
by
Inverse
Variance
(total
return
0.13567)
and
Robust
Optimization
(total
return
0.12119).
In
contrast,
the
Maximum
Sharpe
Ratio
(0.11600)
and
Markowitz
Mean-Variance
strategies
(0.10239)
yield
comparatively
lower
realized
performance.
This
demonstrates
that
strategies
explicitly
optimized
on
historical
data
do
not
necessarily
deliver
superior
out-of-sample
outcomes.
From
a
risk
perspective,
the
Inverse
Variance
strategy
exhibits
the
lowest
Consistency
of
portfolio
allocation
strategies
316
volatility
(0.01162)
and
the
smallest
maximum
drawdown
(0.18125),
proving
its
ability
to
stabilize
fluctuations
by
allocating
greater
weight
to
lower-
variance
assets.
Robust
Optimization
achieves
a
similarly
low
volatility
(0.01194)
and
drawdown
(0.19528).
Conversely,
the
Markowitz
strategy
records
the
highest
volatility
(0.01439)
and
the
largest
maximum
drawdown
(0.23935),
reflecting
its
sensitivity
to
parameter
estimation
error.
Trading
activity
and
turnover
further
distinguish
the
performance
across
strategies.
The
Maximum
Sharpe
Ratio
strategy
records
the
highest
average
turnover
(0.00776)
and
buy/sell
costs
(0.40795),
driven
by
frequent
position
reallocations
from
unstable
parameter
estimates.
The
Markowitz
strategy
exhibits
a
similarly
high
average
turnover
(0.00726).
In
contrast,
the
Equal-
Weighted
(average
turnover
0.00115)
and
Inverse
Variance
strategies
(av-
erage
turnover
0.00310)
maintain
substantially
lower
rebalancing
activity,
resulting
in
superior
allocation
stability
over
time.
In
terms
of
portfolio
structure,
Equal
Weighting
guarantees
uniform
ex-
posure
across
all
constituent
assets,
whereas
Inverse
Variance
achieves
diver-
sification
through
a
risk-balanced
allocation.
Robust
Optimization
avoids
extreme
weight
concentration
while
generating
moderate
returns.
Over-
all,
the
Inverse
Variance
strategy
provides
the
most
balanced
combination
of
risk
control,
reduced
drawdown,
and
allocation
stability,
whereas
the
Equal-Weighted
strategy
stands
out
for
its
superior
cumulative
return
and
implementation
simplicity.
Results
Equal
Weighted
Max
Sharpe
Ratio
Inverse
Variance
Markowitz
Opt.
Robust
Opt.
Total
Return
0.15462
0.116
0.13567
0.10239
0.12119
Sharpe
Ratio
0.057194
0.044587
0.053834
0.036221
0.04764
Volatility
0.012483
0.012399
0.011624
0.014396
0.011948
Average
Turnover
0.0011468
0.0077634
0.0030982
0.0072563
0.0027509
Max
Turnover
0.032336
0.30743
0.16096
0.30629
0.11499
Average
Return
0.00075239
0.00059168
0.00066444
0.00056033
0.00060797
Max
Drawdown
0.19851
0.2026
0.18125
0.23935
0.19528
Average
Buy
Cost
0.060207
0.40795
0.16084
0.36997
0.14165
Average
Sell
Cost
0.060207
0.40795
0.24126
0.36997
0.14165
Table
1:
Strategy
performance
(Assets
A)
2.3.3
Evolution
of
portfolio
value
(Assets
A)
To
illustrate
the
dynamic
behavior
of
each
allocation
strategy
over
time,
Fig.
2
displays
the
equity
curves
tracking
portfolio
value
evolution
across
N.
Shahid,
J.
Guo,
H.
Liu
317
the
backtesting
window.
These
curves
capture
the
cumulative
effect
of
pe-
riodic
rebalancing
and
subsequent
market
movements,
offering
clear
visual
insight
into
wealth
accumulation
patterns,
growth
trajectories,
and
draw-
downs.
Specifically,
the
trajectories
in
Fig.
2
highlight
that
the
Equal-
Weighted
portfolio
achieves
the
steepest
upward
growth
trajectory,
while
the
Inverse
Variance
curve
demonstrates
the
smoothest,
most
stable
trajectory
with
minimal
visible
pullbacks.
Conversely,
the
Markowitz
and
Maximum
Sharpe
Ratio
curves
exhibit
noticeable
structural
dips
and
heightened
fluc-
tuations,
visually
confirming
their
higher
drawdown
vulnerability
and
lower
out-of-sample
stability
compared
to
non-optimized
approaches.
Figure
2:
Evolution
of
portfolio
value
under
competing
investment
strategies
(Assets
A)
The
average
turnover
across
strategies
is
shown
in
Fig.
3
,
providing
insight
into
the
frequency
of
portfolio
rebalancing
and
associated
trading
activity.
As
illustrated,
the
Maximum
Sharpe
Ratio
and
Markowitz
strate-
gies
exhibit
the
highest
turnover
levels,
reflecting
frequent
weight
realloca-
tions
driven
by
sensitivity
to
historical
parameter
estimates.
Conversely,
the
Equal
Weighted
and
Inverse
Variance
strategies
maintain
significantly
lower
turnover,
demonstrating
superior
allocation
stability
over
time.
From
a
practical
standpoint,
lower
rebalancing
activity
makes
these
passive
and
risk-
balanced
approaches
more
favorable
because
it
minimizes
execution
drag
and
Consistency
of
portfolio
allocation
strategies
318
preserves
net
returns.
However,
turnover
alone
is
not
the
sole
benchmark
for
evaluating
portfolio
performance;
it
must
be
assessed
alongside
net
real-
ized
returns,
maximum
drawdowns,
and
volatility
to
capture
the
complete
trade-off
between
implementation
costs
and
risk-adjusted
efficiency.
Figure
3:
Average
portfolio
turnover
across
investment
strategies
(Assets
A)
To
examine
how
portfolio
allocations
evolve
over
time,
the
dynamic
asset
positions
implied
by
each
strategy
are
visualized
using
area
charts
of
daily
portfolio
weights.
Fig.
4
through
Fig.
8
present
the
evolution
of
asset-level
portfolio
weights
over
time
for
the
five
allocation
strategies
considered
in
Analysis
A.
Each
figure
is
displayed
as
a
stacked
area
plot,
where
individual
components
represent
the
proportion
of
total
portfolio
capital
allocated
to
each
as-
set
at
a
given
point
in
time,
and
the
aggregate
height
reflects
the
full-
investment
constraint.
The
temporal
variation
in
these
stacked
profiles
captures
both
passive
changes
induced
by
asset
price
movements
between
rebalancing
dates
and
active
adjustments
arising
from
periodic
portfolio
re-
optimization.
Across
all
figures,
localized
contractions
in
individual
layers
correspond
to
periods
where
the
associated
asset
receives
a
reduced
alloca-
tion,
highlighting
the
dynamic
redistribution
of
capital
across
the
investment
universe.
N.
Shahid,
J.
Guo,
H.
Liu
319
Equal-weighted
strategy
(A)—Asset
allocation
over
time
Fig.
4
presents
the
dynamic
allocation
path
of
the
equal-weighted
strategy,
where
asset
weights
evolve
solely
due
to
price
fluctuations
between
rebalance
dates.
Capital
remains
evenly
distributed
across
all
constituent
stocks,
displaying
smooth
weight
adjustments
over
time.
This
continuous
stability
accounts
for
the
low
trading
turnover
observed
in
Table
1
and
confirms
its
role
as
a
baseline
benchmark
for
Analysis
A.
Figure
4:
Asset-level
portfolio
positions
over
time
(Equal-weighted
strategy,
A)
Maximum
Sharpe
ratio
strategy
(A)—Asset
allocation
over
time
Fig.
5
highlights
the
portfolio
allocation
dynamics
under
the
maximum
Sharpe
ratio
strategy,
where
weight
adjustments
are
driven
by
periodic
re-
calculations
of
risk-adjusted
performance.
The
stacked
area
plot
exhibits
pronounced
reallocation
spikes,
as
capital
is
dynamically
shifted
toward
top-
performing
assets
while
other
position
sizes
contract
or
vanish
completely.
These
notable
weight
swings
align
with
the
elevated
turnover
and
higher
trading
costs
reported
in
Table
1
,
reflecting
the
sensitivity
of
tangency
op-
timization
to
input
parameters.
Inverse
variance
strategy
(A)—Asset
allocation
over
time
Fig.
6
illustrates
the
weight
evolution
for
the
inverse
variance
strategy,
demonstrat-
Consistency
of
portfolio
allocation
strategies
320
Figure
5:
Asset-level
portfolio
positions
over
time
(Maximum
Sharpe
ratio
strategy,
A)
ing
the
persistent
allocation
structure
derived
from
risk-based
weighting.
The
portfolio
maintains
stable
position
sizes
in
low-volatility
constituents
(such
as
JNJ,
CSCO,
and
AAPL),
with
layer
thickness
adjusting
gradu-
ally
across
rebalance
points.
This
defensive
asset
distribution
directly
con-
tributes
to
the
lowest
volatility
and
smallest
maximum
drawdown
recorded
in
Table
1
.
Markowitz
optimization
strategy
(A)—Asset
allocation
over
time
Fig.
7
tracks
the
portfolio
composition
over
time
for
the
Markowitz
mean–
variance
strategy,
capturing
the
ongoing
trade-off
between
return
and
risk.
The
allocation
paths
exhibit
sharper
position
adjustments
across
assets
as
updated
parameter
estimates
modify
the
optimal
weighting
decision.
These
variable
allocation
blocks
help
explain
the
strategy’s
increased
turnover,
higher
trading
expenditure,
and
larger
drawdown
in
Table
1
.
Robust
optimization
strategy
(A)—Asset
allocation
over
time.
Fig.
8
depicts
the
allocation
path
generated
by
the
robust
optimization
strategy,
showing
how
asset
weights
adapt
over
time
while
incorporating
parameter
uncertainty.
Compared
to
the
standard
Markowitz
approach,
the
robust
formulation
leads
to
smoother
and
more
balanced
position
tran-
N.
Shahid,
J.
Guo,
H.
Liu
321
Figure
6:
Asset-level
portfolio
positions
over
time
(Inverse
variance
strategy,
A)
Figure
7:
Asset-level
portfolio
positions
over
time
(Markowitz
optimization
strategy,
A)
Consistency
of
portfolio
allocation
strategies
322
sitions.
By
penalizing
return
estimation
errors,
it
mitigates
extreme
cap-
ital
shifts
while
preserving
portfolio
flexibility
and
maintaining
controlled
volatility
(Table
1
).
Figure
8:
Asset-level
portfolio
positions
over
time
(Robust
optimization
strategy,
A)
2.4
Analysis
B
For
this
part
of
the
analysis,
the
closing
prices
of
JPM,
KO,
MCD,
MMM,
MRK,
MSFT,
NKE,
NVDA,
PG,
SHW,
TRV,
UNH,
V,
VZ,
and
WMT
are
used
to
compute
the
weights
of
the
different
investment
strategies.
To
highlight
differences
in
initial
capital
allocation
across
strategies,
Fig.
9
displays
the
portfolio
weights
computed
at
the
end
of
the
warm-up
period,
where
each
strategy
translates
the
same
historical
price
informa-
tion
into
a
starting
allocation.
The
equal-weighted
strategy
gives
uniform
exposure
to
the
full
asset
set
and
therefore
serves
as
the
broad
diversifica-
tion
benchmark.
Under
the
inverse
variance
strategy,
assets
such
as
KO,
MCD,
PG,
V,
VZ,
and
WMT
receive
comparatively
larger
weights,
indicat-
ing
that
their
estimated
variances
over
the
calibration
window
were
relatively
low
compared
to
other
assets.
The
maximum
Sharpe
ratio
and
Markowitz
strategies
are
more
selective,
assigning
substantial
weight
to
a
narrower
set
of
assets
while
giving
very
small
positions
to
others.
The
robust
optimiza-
N.
Shahid,
J.
Guo,
H.
Liu
323
tion
strategy
keeps
a
wider
spread
of
exposures
than
the
more
aggressive
optimization
rules,
with
visible
emphasis
on
assets
that
combine
moderate
risk
with
stable
historical
performance.
The
strategies
differ
mainly
in
how
they
balance
concentration,
defensive
exposure,
and
sensitivity
to
estimated
returns.
These
initial
weights
should
therefore
be
interpreted
as
calibration-
period
positions
rather
than
evidence
of
long-term
asset
performance.
Figure
9:
Initial
portfolio
weights
(Assets
B)
after
the
40-day
warm-up
period
2.4.1
Evaluation
of
backtest
performance
outcomes
(Assets
B)
After
running
the
backtest,
Table
2
summarizes
the
performance
of
each
strategy
for
Assets
B
using
standard
evaluation
metrics:
realized
return,
volatility,
drawdown,
turnover,
and
trading
cost.
The
market
conditions
and
testing
rules
were
kept
the
same
for
all
methods.
The
interpretation
of
Table
2
must
account
for
the
fact
that
portfolio
de-
cisions
are
made
using
only
information
available
before
each
rebalance
date.
This
point
is
especially
relevant
for
Analysis
B
because
the
optimization-
based
strategies
often
form
concentrated
allocations
from
a
limited
estima-
tion
window.
Their
selected
portfolios
may
appear
efficient
at
the
time
of
construction,
yet
their
realized
performance
depends
on
price
movements
Consistency
of
portfolio
allocation
strategies
324
Results
Equal
Weighted
Max
Sharpe
Ratio
Inverse
Variance
Markowitz
Opt.
Robust
Opt.
Total
Return
0.07382
0.056951
0.046644
0.048307
0.052193
Sharpe
Ratio
0.035303
0.028645
0.023888
0.023782
0.026636
Volatility
0.0096722
0.0091613
0.0089821
0.009571
0.0089964
Average
Turnover
0.0011811
0.0056974
0.0027293
0.0066467
0.0022865
Max
Turnover
0.032776
0.21149
0.10211
0.21104
0.090746
Average
Return
0.00038078
0.00030194
0.00025419
0.00026722
0.0002792
Max
Drawdown
0.11513
0.12427
0.10273
0.12852
0.10863
Average
Buy
Cost
0.061486
0.30048
0.14273
0.34909
0.1195
Average
Sell
Cost
0.061486
0.30048
0.21409
0.34909
0.1195
Table
2:
Strategy
performance
(Assets
B)
that
occur
after
the
weights
are
fixed.
The
empirical
results
show
that
greater
optimization
complexity
can
fail
to
translate
into
stronger
realized
outcomes
in
this
asset
universe.
In
terms
of
return,
the
Equal-Weighted
strategy
achieves
the
highest
to-
tal
(0.07382)
and
average
return
(0.00038),
demonstrating
that
simple,
broad
capital
distribution
effectively
captures
market
recovery
without
relying
on
active
selection
or
frequent
reoptimization.
The
Maximum
Sharpe
Ratio
(0.05695)
and
Robust
Optimization
strategies
(0.05219)
follow,
whereas
the
Markowitz
(0.04831)
and
Inverse
Variance
strategies
(0.04664)
yield
weaker
cumulative
performance.
Inverse
Variance
deliberately
forfeits
upside
po-
tential
by
concentrating
on
low-risk
assets,
while
the
Markowitz
strategy
is
impacted
by
parameter
instability
and
unfavorable
reallocations.
From
a
risk
perspective,
the
Inverse
Variance
strategy
provides
the
stron-
gest
downside
protection,
recording
the
lowest
volatility
(0.00898)
and
the
smallest
maximum
drawdown
(0.10273).
This
confirms
that
the
Assets
B
universe
contains
sufficient
low-risk
constituents
for
a
variance-based
rule
to
mitigate
portfolio
stress.
Robust
Optimization
exhibits
a
similarly
defensive
profile
with
low
volatility
(0.00899)
and
a
controlled
maximum
drawdown
(0.10863).
The
Equal-Weighted
strategy
incurs
slightly
higher
volatility
(0.00967)
but
maintains
a
moderate
drawdown
(0.11513)
due
to
its
broad
asset
distribution,
whereas
the
Markowitz
strategy
experiences
the
largest
maximum
drawdown
(0.12852).
Trading
activity
and
costs
further
separate
the
strategies.
The
Markowitz
strategy
records
the
highest
average
turnover
(0.00665)
and
trading
costs
(0.34909),
followed
by
the
Maximum
Sharpe
Ratio
strategy
(average
turnover
0.00570).
These
high
turnover
rates
highlight
the
sensitivity
of
classical
op-
timization
to
shifting
historical
estimates,
where
additional
trading
activity
N.
Shahid,
J.
Guo,
H.
Liu
325
fails
to
yield
a
performance
advantage.
Conversely,
the
Equal-Weighted
(average
turnover
0.00118)
and
Robust
Optimization
strategies
(average
turnover
0.00229)
maintain
high
allocation
stability
and
minimal
transaction
drag.
Overall,
the
results
demonstrate
a
clear
separation
between
broad
capital
distribution
and
risk-balanced
diversification.
The
Equal-Weighted
strategy
offers
the
strongest
total
return
and
risk-adjusted
efficiency
through
sim-
ple
diversification,
while
the
Inverse
Variance
strategy
remains
the
most
effective
choice
for
capital
preservation
and
downside
control.
Robust
Opti-
mization
serves
as
a
practical
middle
ground
among
optimized
methods
by
maintaining
allocation
stability
while
capturing
higher
returns
than
purely
defensive
approaches.
2.4.2
Evolution
of
portfolio
value
(Assets
B)
Fig.
10
traces
the
portfolio
value
trajectories
for
Assets
B,
illustrating
how
each
strategy
accumulates
wealth
over
the
backtest
period.
Consistent
with
the
trends
in
Analysis
A,
the
Equal-Weighted
strategy
maintains
the
high-
est
equity
curve
throughout
the
horizon,
confirming
its
superior
cumulative
return
capability.
The
Inverse
Variance
curve
displays
the
most
consistent,
low-volatility
progression,
maintaining
a
smooth
upward
slope
even
during
market
pullbacks.
In
contrast,
the
Markowitz
and
Maximum
Sharpe
Ratio
curves
lag
behind,
exhibiting
sharp
drawdowns
and
noticeable
stagnation
that
visually
illustrate
their
out-of-sample
instability
and
sensitivity
to
es-
timation
errors.
The
average
turnover
across
strategies
is
shown
in
Fig.
11
,
providing
insight
into
the
frequency
of
portfolio
rebalancing
and
associated
trading
activity.
Mirroring
the
behavior
observed
in
Analysis
A,
the
results
for
Assets
B
confirm
that
the
Maximum
Sharpe
Ratio
and
Markowitz
strate-
gies
generate
the
highest
turnover,
whereas
the
Equal
Weighted
and
Inverse
Variance
models
maintain
the
lowest
rebalancing
requirements.
This
con-
sistency
reinforces
that
parameter-dependent
optimizations
persistently
in-
cur
higher
trading
frequency
across
different
asset
pools,
while
risk-weighted
and
static
allocations
offer
greater
operational
stability.
Consequently,
while
low
turnover
makes
Equal
Weighted
and
Inverse
Variance
allocations
struc-
turally
more
favorable
for
cost
management,
rebalancing
frequency
remains
just
one
dimension
of
strategy
selection
and
must
be
weighed
against
draw-
down
control
and
net
realized
returns.
To
examine
how
portfolio
allocations
evolve
over
time,
the
dynamic
asset
positions
implied
by
each
strategy
are
visualized
using
area
charts
of
daily
Consistency
of
portfolio
allocation
strategies
326
Figure
10:
Evolution
of
portfolio
value
under
competing
investment
strate-
gies
(Assets
B)
Figure
11:
Average
portfolio
turnover
across
investment
strategies
(Assets
B)
N.
Shahid,
J.
Guo,
H.
Liu
327
portfolio
weights.
Fig.
12
through
Fig.
16
present
the
evolution
of
asset-level
portfolio
weights
over
time
for
the
allocation
strategies
considered
in
Analysis
B.
The
stacked
area
plots
show
how
each
method
distributes
capital
across
the
same
asset
universe
and
how
those
distributions
change
as
prices
move
and
rebalancing
decisions
occur.
Equal-weighted
strategy
(B)—Asset
allocation
over
time
Fig.
12
illustrates
the
time-varying
portfolio
composition
of
the
equal-weighted
strat-
egy.
The
allocation
remains
broadly
distributed,
and
changes
in
the
stacked
areas
mainly
reflect
asset
price
movements
between
rebalancing
dates.
This
pattern
explains
the
strategy’s
low
turnover
and
shows
why
it
functions
as
a
stable
benchmark
in
Analysis
B.
Figure
12:
Asset-level
portfolio
positions
over
time
(Equal-weighted
strategy,
B)
Maximum
Sharpe
ratio
strategy
(B)—Asset
allocation
over
time
Fig.
13
depicts
the
evolution
of
asset
allocations
under
the
maximum
Sharpe
ratio
strategy.
The
area
chart
displays
more
abrupt
changes
than
the
equal-
weighted
and
inverse
variance
strategies,
with
capital
shifting
toward
se-
lected
assets
as
risk-adjusted
return
estimates
are
updated.
Several
layers
Consistency
of
portfolio
allocation
strategies
328
expand
or
contract
sharply
at
rebalancing
points,
and
some
asset
exposures
become
temporarily
very
small
or
nearly
disappear
from
the
stacked
area
plot.
These
visible
reallocations
are
consistent
with
the
higher
turnover
re-
ported
in
Table
2
and
with
the
sensitivity
of
Sharpe-ratio
optimization
to
estimated
returns
and
covariance
inputs.
Figure
13:
Asset-level
portfolio
positions
over
time
(Maximum
Sharpe
ratio
strategy,
B)
Inverse
variance
strategy
(B)—Asset
allocation
over
time
Fig.
14
presents
the
allocation
dynamics
of
the
inverse
variance
strategy.
The
port-
folio
keeps
relatively
persistent
exposure
to
lower-volatility
assets,
and
its
weights
adjust
more
gradually
over
time.
This
stable
structure
supports
the
low
volatility
and
drawdown
results
observed
in
Table
2
.
Markowitz
optimization
strategy
(B)—Asset
allocation
over
time
Fig.
15
shows
the
evolution
of
portfolio
weights
for
the
Markowitz
strategy.
The
allocation
path
contains
sharper
shifts
across
assets,
reflecting
the
strat-
egy’s
sensitivity
to
estimated
expected
returns
and
covariance
relationships.
This
behaviour
helps
explain
its
higher
turnover,
larger
trading
cost,
and
weaker
drawdown
control.
N.
Shahid,
J.
Guo,
H.
Liu
329
Figure
14:
Asset-level
portfolio
positions
over
time
(Inverse
variance
strat-
egy,
B)
Figure
15:
Asset-level
portfolio
positions
over
time
(Markowitz
optimization
strategy,
B)
Consistency
of
portfolio
allocation
strategies
330
Robust
optimization
strategy
(B)—Asset
allocation
over
time
Fig.
16
illustrates
the
asset
allocation
path
generated
by
the
robust
optimization
strategy.
Compared
with
the
standard
Markowitz
allocation,
the
robust
strategy
produces
smoother
and
more
balanced
position
changes.
Its
al-
location
path
reflects
the
effect
of
accounting
for
uncertainty
in
expected
returns,
which
reduces
extreme
reallocations
while
preserving
adaptability.
Figure
16:
Asset-level
portfolio
positions
over
time
(Robust
optimization
strategy,
B)
Across
these
figures,
the
defining
feature
of
Analysis
B
is
the
contrast
be-
tween
stable
broad
exposure
and
concentrated
optimization.
Equal
weight-
ing
produces
the
smoothest
benchmark
allocation,
inverse
variance
delivers
a
defensive
risk-based
profile,
and
robust
optimization
moderates
the
insta-
bility
associated
with
standard
mean–variance
optimization.
The
maximum
Sharpe
ratio
and
Markowitz
strategies
show
more
visible
reallocation
blocks,
which
match
their
higher
turnover
and
less
stable
realized
performance.
For
Assets
B,
allocation
stability
and
controlled
risk
exposure
contribute
more
reliably
to
long-term
performance
than
frequent
re-optimization
driven
by
unstable
historical
parameter
estimates.
N.
Shahid,
J.
Guo,
H.
Liu
331
Criterion
Equal
Weighted
(EW)
Inverse
Variance
(IV)
Robust
Optimi-
zation
(RO)
Max
Sharpe
Ratio
(MSR)
Markowitz
Mean-
Variance
(MV)
Return
performance
Highest
in
A
and
B
Second
in
A,
lowest
in
B
Moderate
Moderate-
low
Lowest
in
A,
second
lowest
in
B
Volatility
control
Moderate
Lowest
Near-lowest
Moderate
Highest
Maximum
drawdown
Moderate
Lowest
Second
lowest
Higher
Highest
Turnover
Lowest
Low-
moderate
Low
Highest
Highest
Transaction
costs
Lowest
Low
Low
Highest
Highest
Allocation
stability
Highest
High
High
Low
Low
Diversifi-
cation
Maximum
Risk-based
Balanced
Concen-
trated
Concen-
trated
Sensitivity
to
estimation
error
None
Low
Controlled
High
Very
high
Practical
portfolio
construction
Excellent
Excellent
Good
Weak
Weak
Table
3:
Comparative
backtesting
summary
from
Analysis
A
and
Analysis
B
Consistency
of
portfolio
allocation
strategies
332
3
Discussion
The
results
in
Table
3
demonstrate
broad
structural
consistency
across
both
asset
universes
A
and
B.
While
the
overall
hierarchy
between
heuristic
and
optimization-driven
models
holds,
specific
return
rankings
vary
slightly
be-
tween
the
two
pools
(e.g.,
Inverse
Variance
yields
the
second-highest
return
in
Analysis
A
but
ranks
lower
in
Analysis
B,
whereas
Maximum
Sharpe
Ratio
improves
its
return
rank
in
Analysis
B).
Nevertheless,
key
perfor-
mance
characteristics—such
as
volatility
control
and
turnover
behavior—
remain
stable.
While
the
Equal
Weighting
method
yielded
the
top
cumula-
tive
return
in
both
groups,
the
Inverse
Variance
framework
systematically
achieved
the
lowest
volatility,
minimal
maximum
drawdowns,
and
modest
turnover
while
preserving
competitive
return
levels,
making
it
the
most
bal-
anced
allocation
overall.
Conversely,
despite
their
theoretical
foundation,
the
Markowitz
and
Maximum
Sharpe
Ratio
strategies
exhibited
elevated
turnover
rates,
greater
transaction
drag,
and
lower
realized
returns.
Ro-
bust
Optimization
enhanced
weighting
stability
relative
to
classical
mean–
variance
models,
yet
its
performance
remained
less
dependable
than
Inverse
Variance.
While
the
Inverse
Variance
strategy
appears
to
offer
the
most
balanced
overall
performance,
the
results
also
demonstrate
that
portfolio
allocation
decisions
depend
strongly
on
the
investor’s
objective.
The
Equal
Weighted
strategy
consistently
generated
the
highest
realized
returns
in
both
analy-
ses,
making
it
attractive
when
return
maximization
is
the
primary
goal.
In
contrast,
the
Inverse
Variance
strategy
delivered
the
lowest
volatility
and
smallest
maximum
drawdowns,
indicating
superior
downside-risk
control.
It
also
maintained
relatively
low
turnover
and
transaction
costs
compared
with
the
Maximum
Sharpe
Ratio
and
Markowitz
strategies,
whose
frequent
reallocations
increased
implementation
costs
without
producing
superior
re-
alized
outcomes.
These
findings
suggest
that
investors
seeking
growth
may
prefer
Equal
Weighting,
whereas
investors
emphasizing
risk
management,
capital
preservation,
and
allocation
stability
would
likely
favor
the
Inverse
Variance
approach.
Overall,
the
latter
provides
the
strongest
combination
of
risk
control,
turnover
management,
and
drawdown
reduction,
making
it
a
compelling
choice
for
practical
portfolio
allocation.
An
additional
implication
of
the
comparative
analysis
concerns
the
iden-
tification
of
assets
suitable
for
subsequent
portfolio
optimization.
The
volati-
lity-based
investigation
[
18
]
of
KSE-30
equities
showed
that
highly
volatile
stocks
were
generally
excluded
from
optimized
portfolios,
whereas
assets
with
lower
or
moderate
sensitivity
to
market
movements
contributed
more
N.
Shahid,
J.
Guo,
H.
Liu
333
meaningfully
to
portfolio
construction.
Similarly,
the
Black-Litterman
anal-
ysis
[
19
]
retained
only
a
limited
set
of
assets
with
favorable
return
and
risk
characteristics
after
blending
market
equilibrium
returns
with
analyst
views.
The
appearance
of
assets
such
as
HBL,
LUCK,
and
POL—constituents
of
the
Pakistan
Stock
Exchange
KSE-30
index
examined
in
[
19
]—within
the
final
Black-Litterman
allocation
suggests
that
securities
exhibiting
both
ac-
ceptable
volatility
characteristics
and
favorable
expected-return
profiles
may
represent
promising
candidates
for
future
portfolio
construction.
Although
a
formal
combined
optimization
framework
would
be
required
to
confirm
this
observation,
the
current
findings
provide
a
preliminary
indication
that
infor-
mation
from
both
analyses
may
assist
in
screening
equities
for
subsequent
optimal
portfolio
development
and
future
Black-Litterman
applications.
Furthermore,
the
comparison
highlights
an
important
limitation
of
his-
torically
popular
optimization-based
investment
methods.
In
portfolio
the-
ory,
the
Maximum
Sharpe
Ratio
strategy
is
frequently
regarded
as
an
at-
tractive
allocation
rule
because
it
seeks
the
highest
risk-adjusted
return
on
the
efficient
frontier.
However,
the
backtesting
results
obtained
in
both
analyses
indicate
that
this
theoretical
advantage
did
not
translate
into
con-
sistently
superior
realized
performance.
The
strategy
exhibited
substantially
higher
turnover
and
transaction
costs
than
simpler
allocation
rules,
while
its
realized
returns
and
risk-adjusted
outcomes
remained
comparatively
mod-
est.
Similar
behavior
was
observed
for
the
Markowitz
strategy.
These
find-
ings
emphasize
that
allocations
derived
from
historical
optimization
may
be
highly
sensitive
to
estimation
error
and
changing
market
conditions.
Conse-
quently,
relying
exclusively
on
historically
estimated
inputs
may
not
always
be
sufficient
for
index
investment
decisions,
particularly
when
implementa-
tion
costs
and
allocation
stability
are
important
considerations.
Ultimately,
this
analysis
demonstrates
that
the
Inverse
Variance
strategy
provides
the
most
balanced
overall
profile,
while
revealing
broadly
consistent
structural
performance
patterns
across
two
independent
asset
universes.
Al-
though
asset-universe
composition
introduces
slight
variations
in
total
return
rankings
for
specific
strategies,
both
evaluations
yield
identical
overarching
conclusions
regarding
return
generation,
risk
control,
turnover
behavior,
and
allocation
stability.
Specifically,
simpler
diversification
and
risk-aware
ap-
proaches
consistently
match
or
outperform
complex
optimization
methods
on
realized
portfolio
outcomes.
This
indicates
that
the
structural
stability
of
the
allocation
mechanism
is
more
vital
to
performance
than
aggressive
op-
timization
based
on
historical
estimates.
Because
this
pattern
holds
across
multiple
criteria
and
independent
datasets,
the
observed
behavior
reflects
a
robust
portfolio
allocation
principle
rather
than
a
dataset-specific
artifact.
Consistency
of
portfolio
allocation
strategies
334
4
Conclusion
This
study
was
conducted
to
examine
whether
different
portfolio
allocation
strategies
produce
consistent
investment
outcomes
when
applied
to
differ-
ent
groups
of
equities
within
the
same
market
environment.
Using
one
year
of
daily
closing
price
data
from
the
Dow
Jones
Industrial
Average
(DJIA)
constituents,
two
independent
analyses
were
performed
on
separate
sets
of
fifteen
assets.
Five
portfolio
allocation
strategies,
namely
Equal
Weighted,
Maximum
Sharpe
Ratio,
Inverse
Variance,
Markowitz
Mean-Variance
Op-
timization,
and
Robust
Optimization,
were
evaluated
under
an
identical
backtesting
framework
with
periodic
rebalancing.
The
main
contribution
of
this
work
is
the
direct
comparison
of
simple
diversification
approaches,
risk-based
allocation
methods,
and
optimization-
based
portfolio
strategies
across
two
independent
asset
universes
using
the
same
evaluation
methodology.
This
allows
the
robustness
of
strategy
per-
formance
to
be
assessed
rather
than
relying
on
results
from
a
single
asset
set.
The
evidence
obtained
from
both
analyses
shows
that
strategy
per-
formance
is
highly
consistent
across
the
two
asset
universes.
The
Equal
Weighted
strategy
produced
the
highest
realized
returns,
while
the
Inverse
Variance
strategy
consistently
achieved
the
lowest
volatility,
the
smallest
drawdowns,
and
relatively
low
turnover.
In
contrast,
the
Maximum
Sharpe
Ratio
and
Markowitz
strategies
exhibited
higher
turnover,
higher
transac-
tion
costs,
and
weaker
realized
performance
despite
their
theoretical
opti-
mization
advantages.
The
Robust
Optimization
strategy
provided
a
com-
promise
between
return
generation
and
risk
control
but
did
not
consistently
outperform
the
Inverse
Variance
approach.
The
principal
conclusion
supported
by
the
results
is
that
stable
and
risk-aware
allocation
methods
can
be
more
effective
in
practice
than
con-
ventional
strategies
that
depend
heavily
on
estimates
of
expected
returns.
Across
both
analyses,
simple
diversification
and
variance-based
risk
control
delivered
more
consistent
portfolio
outcomes
than
more
complex
optimiza-
tion
procedures.
These
findings
suggest
that
portfolio
allocation
decisions
may
benefit
more
from
robustness,
stability,
and
risk
management
than
from
aggressive
optimization
of
historical
return
estimates.
N.
Shahid,
J.
Guo,
H.
Liu
335
5
Limitations
of
the
study
The
analysis
is
based
on
a
single
year
of
historical
data
and
two
subsets
of
DJIA
constituents.
Consequently,
the
findings
may
be
influenced
by
the
specific
market
conditions
observed
during
the
study
period.
Although
the
consistency
of
results
across
both
asset
universes
strengthens
the
conclu-
sions,
the
performance
of
the
strategies
may
differ
under
alternative
market
regimes
or
longer
investment
horizons.
In
addition,
the
two
asset
subsets
were
formed
by
ticker
order
rather
than
by
a
sector-stratified
procedure;
a
sector-balanced
split
of
the
DJIA
constituents
would
help
confirm
whether
the
observed
consistency
in
strategy
rankings
is
robust
to
differences
in
sec-
tor
composition
across
the
two
universes.
6
Future
research
directions
Future
work
may
extend
the
analysis
to
multiple
years
of
data
and
ad-
ditional
equity
markets
to
examine
the
robustness
of
the
observed
results
across
different
market
environments.
The
findings
of
this
study
may
also
be
combined
with
volatility-based
screening
and
Black-Litterman
portfolio
optimization
frameworks
to
investigate
whether
assets
consistently
favored
by
risk-aware
allocation
strategies
can
improve
portfolio
construction
and
asset
selection
decisions.
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