Calculate Stock Portfolio Weight Dispersion from Model
Use this tool to calculate stock portfolio weight dispersion from model, visualize deviations, and learn how to tighten alignment between actual weights and your target model.
Calculator: Calculate Stock Portfolio Weight Dispersion from Model
Enter how many positions are in the actual portfolio and model.
Comma-separated percentages that sum near 100; no negatives.
Comma-separated percentages matching the number of holdings.
Set the maximum acceptable absolute gap between actual and model for each holding.
Weight dispersion: 3.0% average absolute deviation
Formula: Average absolute deviation = (Σ|actual – model|) / N. Dispersion captures the average gap between actual and model weights; halved dispersion approximates turnover needed to rebalance toward the model.
Actual vs Model Weight Chart
Actual WeightsModel Weights
Holdings and deviations table
Holding
Actual %
Model %
Absolute Deviation %
What is calculate stock portfolio weight dispersion from model?
Calculate stock portfolio weight dispersion from model is the process of measuring how far a live equity portfolio has drifted from its target allocation blueprint. Investors use calculate stock portfolio weight dispersion from model when they want to ensure their active or passive sleeves stay faithful to strategic weights. Quant managers, CIOs, advisors, and risk teams use calculate stock portfolio weight dispersion from model to control unintended bets and rebalance efficiently. A common misconception about calculate stock portfolio weight dispersion from model is that it only matters when sums exceed 100%; in reality, even small tracking gaps compound risk exposures. Another misconception is that calculate stock portfolio weight dispersion from model is only for index trackers, but active managers also rely on calculate stock portfolio weight dispersion from model to maintain discipline around conviction sizing.
calculate stock portfolio weight dispersion from model Formula and Mathematical Explanation
The core math behind calculate stock portfolio weight dispersion from model is built on absolute and squared deviations. For each holding i, deviation di = actuali − modeli. The absolute deviation |di| describes how much the position strays from the plan. Calculate stock portfolio weight dispersion from model then aggregates these deviations to show total slippage and average drift.
Step-by-step to calculate stock portfolio weight dispersion from model:
Compute di = ai − mi for every holding.
Take absolute values |di| to measure magnitude of drift.
Sum all |di| to find total absolute deviation.
Divide by N holdings to get average absolute dispersion.
Optionally compute mean squared deviation Σ(di2)/N to approximate tracking variance.
Count holdings where |di| exceeds a tolerance to prioritize rebalancing.
Calculate stock portfolio weight dispersion from model highlights rebalance turnover because roughly half of the absolute deviation must trade to realign weights.
Variables table
Variables used to calculate stock portfolio weight dispersion from model
Variable
Meaning
Unit
Typical range
ai
Actual weight of holding i
%
0–30
mi
Model weight of holding i
%
0–30
di
Difference ai−mi
%
-30–30
|di|
Absolute deviation
%
0–15
N
Number of holdings
count
5–200
Dispersion
Average absolute deviation
%
0–8
MSD
Mean squared deviation
%²
0–40
Tolerance
Maximum allowed |di|
%
1–5
Practical Examples (Real-World Use Cases)
Example 1: Dividend tilt portfolio
A dividend ETF clone wants to calculate stock portfolio weight dispersion from model with five holdings. Actual weights are 25%, 20%, 18%, 22%, 15% while the model is equal-weight 20% each. Calculate stock portfolio weight dispersion from model gives average absolute dispersion of 3.0%, total absolute deviation 15%, and two holdings exceed a 3% tolerance. The interpretation is that roughly 7.5% turnover brings the basket back to the model.
Example 2: Active growth sleeve
An active manager uses calculate stock portfolio weight dispersion from model after momentum winners stretched sizing. Actual weights are 30%, 24%, 16%, 18%, 12% against a model of 22%, 22%, 20%, 18%, 18%. Calculate stock portfolio weight dispersion from model yields total absolute deviation 18%, average dispersion 3.6%, and three holdings over a 2% tolerance. The manager sees that dispersion is concentrated in the top two names and trims them first.
How to Use This calculate stock portfolio weight dispersion from model Calculator
Enter the number of holdings, actual weights, model weights, and tolerance. The calculator will calculate stock portfolio weight dispersion from model in real time, showing average absolute deviation, total absolute deviation, maximum drift, tracking-like variance, and which holdings breach tolerance. Read the chart to compare actual versus model visually and use the table to target trades. Because calculate stock portfolio weight dispersion from model updates instantly, you can test hypothetical trades before executing.
Key Factors That Affect calculate stock portfolio weight dispersion from model Results
Cash flows: subscriptions or redemptions distort allocations and raise calculate stock portfolio weight dispersion from model.
Corporate actions: splits or spin-offs change weights and influence calculate stock portfolio weight dispersion from model.
Trading costs: high costs delay rebalancing, letting calculate stock portfolio weight dispersion from model expand.
Tax constraints: deferring gains can keep calculate stock portfolio weight dispersion from model elevated.
Risk limits: factor or sector caps force selective trades that shape calculate stock portfolio weight dispersion from model.
Benchmark changes: new targets reset the baseline for calculate stock portfolio weight dispersion from model.
Drift thresholds: tighter tolerances make calculate stock portfolio weight dispersion from model trigger more often.
Frequently Asked Questions (FAQ)
How often should I calculate stock portfolio weight dispersion from model? Weekly or after large price moves keeps dispersion controlled.
What if sums are not 100%? The calculator normalizes patterns, but large gaps distort calculate stock portfolio weight dispersion from model; align sums first.
Can I use calculate stock portfolio weight dispersion from model for ETFs? Yes, it works for any weighted basket.
Does turnover equal total deviation? Roughly half of total deviation is traded to fix calculate stock portfolio weight dispersion from model.
How do taxes affect calculate stock portfolio weight dispersion from model? Tax-aware traders may allow higher dispersion to defer gains.
Is mean squared deviation necessary? It sharpens risk views when you calculate stock portfolio weight dispersion from model.
Can tolerance differ by holding? Not in this tool, but per-name tolerances refine calculate stock portfolio weight dispersion from model.
What if data quality is poor? Garbage in leads to unreliable calculate stock portfolio weight dispersion from model; validate holdings first.
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var chart;
function parseWeights(text){
var parts=text.split(",");
var arr=[];
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function updateDispersion(){
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var actualArr=parseWeights(document.getElementById("actualWeights").value);
var modelArr=parseWeights(document.getElementById("modelWeights").value);
var tolerance=parseFloat(document.getElementById("tolerance").value);
var valid=validateInputs(count,actualArr,modelArr,tolerance);
if(!valid){return;}
var absSum=0;
var maxDev=0;
var msdSum=0;
var breaches=0;
var deviations=[];
for(var i=0;imaxDev){maxDev=abs;}
if(abs>tolerance){breaches++;}
}
var avgDisp=absSum/count;
var msd=msdSum/count;
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document.getElementById("intermediate1″).innerHTML="Total absolute deviation: "+absSum.toFixed(2)+"%";
document.getElementById("intermediate2″).innerHTML="Max single holding deviation: "+maxDev.toFixed(2)+"%";
document.getElementById("intermediate3″).innerHTML="Tracking-like variance (mean squared deviation): "+msd.toFixed(2);
document.getElementById("intermediate4″).innerHTML="Holdings breaching tolerance: "+breaches+" positions above limit";
updateTable(actualArr,modelArr,deviations);
drawChart(actualArr,modelArr);
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