Position Sizing Methods: Fixed Risk, ATR & Kelly

Position sizing converts a loss budget into a tradable quantity. The normalized calculation is:

Quantity = Risk budget ÷ Planned loss per tradable unit

The calculation is incomplete until the price distance is converted through the instrument's actual share, tick, point, pip, contract, multiplier, or currency value. Fees, spread, adverse fills, minimum quantity, rounding, margin, buying power, and correlated exposure can reduce the final size or make the trade unsuitable for the stated budget.

Key takeaways:

Position size, capital allocation, notional exposure, margin, and maximum loss are different measurements.
A percentage such as 1% or 2% is a chosen risk convention, not a universal safe level.
Stocks, futures, forex, options, and crypto require different unit conversions.
A stop price does not guarantee the execution price or cap the actual loss.
Volatility and Kelly-style methods change the sizing input; neither creates a trading edge.
A sizing method should be tested on the same chronological trades, with costs, rounding, leverage, gaps, and portfolio limits included.

This page owns position-sizing method comparison, cross-market unit conversion, volatility/ATR sizing, Kelly-style methods, implementation controls, portfolio constraints, and model testing. The beginner position-sizing guide owns the introductory fixed-risk formula, drawdown/recovery explanation, and replay drill. The 1% rule guide owns that exact percentage convention, while the portfolio heat guide owns detailed combined-position exposure.

Start by Separating Five Different Numbers

Sizing errors often begin before the formula because several distinct measurements are treated as interchangeable.

Measurement	What it answers	Why it is not the same as planned loss
Position quantity	How many shares, contracts, lots, or coins are held?	Quantity has no risk meaning until price sensitivity is known
Capital allocation	How much cash or account capital is assigned?	A large cash position can have a nearby invalidation; a small leveraged position can carry large exposure
Notional exposure	What underlying market value does the position represent?	Notional measures exposure, not necessarily the amount expected to be lost at an exit
Margin or buying power	How much collateral does the broker require?	Margin is an operational requirement and can change; it is not a guaranteed maximum loss
Planned loss budget	How much loss is allowed under the documented sizing scenario?	Actual loss can still exceed it because of fills, gaps, costs, assignment, liquidation, or model error

A $10,000 stock purchase, one futures contract, one option contract, and one leveraged forex position cannot be compared by quantity alone. Their price sensitivity, contract specifications, financing, execution path, and loss boundaries differ.

The Normalized Position Sizing Framework

Use a loss budget rather than starting with a desired share or contract count.

Let:

A = the account basis used by the plan;
r = the selected risk fraction, when a percentage method is used;
B = the loss budget in account currency;
D = entry-to-invalidation distance in the instrument's price units;
V = account-currency value of one price unit for one tradable unit;
C = estimated round-trip fees, spread and other costs per tradable unit;
F = adverse-fill allowance per tradable unit;
L = planned loss per tradable unit;
Q = final tradable quantity.

When the budget is percentage-based:

B = A × r

Convert the chart distance into money:

L = (D × V) + C + F

Then calculate and round down:

Qraw = B ÷ L
Q = floor Qraw to the broker's permitted quantity increment

The calculation must pass separate checks for:

available cash, margin and buying power;
broker and exchange minimums or maximums;
concentration and correlated exposure;
gap, halt, assignment, liquidation and adverse-fill scenarios;
whether the required tradable increment is too large for the budget.

When one minimum unit already exceeds the budget, zero units is a valid output. The formula does not require forcing a trade, widening an invalidation without a chart reason, increasing leverage, or accepting a larger loss budget.

Choose the Account Basis Before Choosing the Percentage

“Risk 1% of the account” is ambiguous unless the account basis is defined.

Possible bases include:

start-of-day equity;
previous close equity;
current net liquidation value;
settled cash;
strategy-assigned capital;
peak equity;
a deliberately reduced risk capital figure.

Each produces a different budget. Current equity changes intraday; peak equity can keep size elevated during a drawdown; settled cash may exclude available margin; strategy-assigned capital may ignore shared exposure elsewhere in the account.

Record the chosen basis and update timing. Do not alternate between account values after seeing whether a setup looks attractive.

A Worked Stock Example with Costs and Rounding

Assume a hypothetical long stock plan:

account basis: $24,000;
selected loss budget: $240;
proposed entry: $48.60;
invalidation reference: $46.90;
price distance: $1.70 per share;
estimated round-trip costs and adverse-fill allowance: $0.10 per share.

The planned loss per share is:

$1.70 + $0.10 = $1.80

The raw quantity is:

$240 ÷ $1.80 = 133.33 shares

Rounded down to whole shares:

133 shares

Planned worksheet loss:

133 × $1.80 = $239.40

The notional position is approximately $6,463.80, but that is not the planned loss. The calculation still does not guarantee a $239.40 realized loss. A gap below the reference, a delayed fill, a halt, a widened spread, or a broker restriction can produce a different outcome.

For a short stock position, the distance is measured upward from entry to the invalidation reference. Short selling also introduces borrow availability, borrow cost, recall, buy-in, dividend and corporate-action issues. Because a stock price can rise without a fixed ceiling, a planned stop does not convert a short position into a truly capped-loss instrument. The short-selling mechanics guide owns those details.

Cross-Market Conversion: Use the Instrument's Actual Unit

The numerator can be the same loss budget while the denominator changes by market.

Market	Tradable quantity	Convert price movement using	Important implementation checks
Stocks and ETFs	Shares or fractional shares	Currency distance per share	Fractional-share availability, spread, liquidity, gaps, short borrow, corporate actions
Futures	Whole contracts	Points × value per point, or ticks × tick value	Exact contract month/specification, minimum tick, contract multiplier, margin, daily limits, roll and session
Spot forex / CFDs	Units or lot increments	Stop pips × pip value in account currency	Pair direction, quote currency, account-currency conversion, lot step, spread, financing, leverage and broker terms
Long options	Contracts	Option-price change × contract multiplier	Standard versus adjusted contract, premium, liquidity, Greeks, expiry, exercise and assignment procedures
Multi-leg options	Strategy units	Strategy-specific scenario loss	Leg ratios, net debit/credit, width, execution sequence, early assignment, expiration and broker margin
Crypto spot	Coin or token quantity	Currency distance per coin/token	Venue precision, minimum order, fee tier, spread, slippage, fragmented liquidity and counterparty risk
Crypto derivatives	Contracts or units	Venue-specific contract value	Linear versus inverse contract, collateral currency, liquidation, funding and mark-price rules

Do not copy a share formula into a futures, options, forex, or inverse-crypto contract without changing the value-per-unit term.

Futures Position Sizing: Point Value and Tick Value

For a futures contract:

Planned loss per contract
= stop distance in points × value per point
+ costs
+ adverse-fill allowance

The same calculation can be expressed in ticks:

Planned loss per contract
= stop distance in ticks × tick value
+ costs
+ adverse-fill allowance

The exchange specification is the source of truth. CME Group states that the Micro E-mini S&P 500 futures contract is $5 times the index with a 0.25-point minimum tick. That implies $1.25 per minimum tick for that contract, but specifications should be checked again for the exact product and contract being traded.

Hypothetical MES worksheet:

loss budget: $250;
stop distance: 12 index points;
point value: $5;
estimated fees and adverse-fill allowance: $7.50 per contract.

Price-distance loss = 12 × $5 = $60
Planned loss per contract = $60 + $7.50 = $67.50
Raw contracts = $250 ÷ $67.50 = 3.70
Rounded contracts = 3
Planned worksheet loss = 3 × $67.50 = $202.50

The unused budget is not an error. Futures trade in whole contracts. Four contracts would exceed the stated worksheet budget.

Margin is checked after the risk calculation. A broker's intraday or overnight margin requirement does not replace the point-value calculation and is not a maximum-loss promise. Price limits, liquidation rules, session transitions and broker risk controls can also change the realized outcome.

Forex Position Sizing: Pip Value Must Reach Account Currency

A forex worksheet needs:

the pair;
the position units or lot size;
the pip definition used by the broker;
pip value for that quantity;
conversion into the account currency;
spread, commission, financing and adverse-fill assumptions.

For a USD account trading EUR/USD, a 10,000-unit position commonly has a $1 value per 0.0001 pip because USD is the quote currency. Other pair/account-currency combinations require conversion, and broker contract definitions can differ.

Hypothetical EUR/USD worksheet:

loss budget: $170;
stop distance: 35 pips;
test unit: 10,000 currency units;
pip value for the test unit: $1 per pip;
estimated total spread, commission and adverse-fill allowance: $5 per test unit.

Planned loss per 10,000 units = (35 × $1) + $5 = $40
Raw test units = $170 ÷ $40 = 4.25
Rounded position = 4 × 10,000 = 40,000 units
Planned worksheet loss = 4 × $40 = $160

This is an arithmetic example, not a recommended lot size. Verify the broker's lot increment, pip convention, account-currency conversion, financing, margin and stop behavior. The CFTC warns that leveraged forex losses can exceed the amount deposited.

Options Position Sizing: Multiply the Quoted Premium Correctly

The legacy version of this article treated a $2.50 option-price move as a $2.50 loss per contract. That is incorrect for a standard U.S. equity option.

OCC states that each standard equity option generally represents 100 shares, while corporate actions can create adjusted contracts that represent something else. OCC also states that one premium point equals $100 for standard equity options.

For a standard long option contract:

Option-value change per contract
= option-price change × contract multiplier

Hypothetical long-call worksheet:

loss budget: $300;
option entry premium: $2.40;
re-evaluation or stop reference: $1.55;
quoted premium distance: $0.85;
standard multiplier: 100;
estimated costs and adverse-fill allowance: $10 per contract.

Price-distance loss per contract = $0.85 × 100 = $85
Planned loss per contract = $85 + $10 = $95
Raw contracts = $300 ÷ $95 = 3.15
Rounded contracts = 3
Planned worksheet loss = 3 × $95 = $285

The planned stop scenario is not the same as maximum loss. The Options Industry Council explains that a long call held through expiration can lose the premium paid. In this example, the premium outlay is $240 per contract before fees, so three contracts can lose substantially more than the $285 stop-based worksheet if the exit does not occur as modeled.

Multi-leg and short-option strategies need strategy-specific scenario analysis. A quoted premium, a margin requirement, or a simple underlying stop distance is not a universal loss measure. Verify adjusted contracts, settlement, exercise, assignment, expiration, leg ratios and broker procedures through the broker and the official product documents. The options beginner guide provides the broader options boundary.

Why a Stop Price Is Not a Loss Guarantee

A chart invalidation level, a stop trigger, a stop order and an execution price are separate concepts.

FINRA explains that a stop order becomes a market order after the stop price is reached and can execute materially away from the trigger in a fast or volatile market. Investor.gov likewise notes that a market order prioritizes execution but does not guarantee the execution price.

A sizing record should therefore contain at least three loss estimates:

Scenario	Purpose	Example input
Reference-loss scenario	Compares ideas using the intended invalidation level	Entry-to-reference distance plus normal costs
Adverse-fill scenario	Tests a plausible worse execution	Wider spread, extra ticks/pips, delayed fill or partial fill
Gap/stress scenario	Tests discontinuous movement or operational failure	Overnight gap, halt, daily limit, assignment, liquidation or unavailable exit

The stress scenario does not need to predict the worst possible outcome. Its purpose is to show that the planned budget is conditional, not guaranteed. The stop-loss and take-profit planning guide owns stop-level, order-type and bracket-order implementation.

Position Sizing Methods Compared

Different methods change either the loss budget, the reference distance, or the portfolio exposure target.

Method	Main rule	Useful for	Main limitation
Fixed units	Trade the same quantity each time	Simple operational baselines	Monetary risk changes with price sensitivity and stop distance
Fixed notional	Allocate the same currency amount	Allocation comparisons	Does not normalize loss at invalidation
Fixed dollar risk	Keep the loss budget constant	Stable-dollar experiments	Does not automatically scale with account equity
Fixed fractional	Loss budget is a fixed fraction of the selected account basis	Scaling risk with equity	Percentage choice is arbitrary and realized loss can exceed the budget
Volatility-distance sizing	Use an ATR, standard-deviation or range-based distance, then solve for quantity	Comparing instruments with different movement scales	Indicator version and multiplier can be overfit; volatility is not directional edge
Portfolio-volatility targeting	Size toward a target volatility contribution	Multi-asset systematic portfolios	Requires return, volatility and covariance estimates; leverage and regime changes matter
Kelly-style sizing	Size from estimated win probability and payoff distribution to target log growth	Research on repeatable probabilistic systems	Extremely sensitive to estimated edge, dependence, tail loss, costs and nonstationarity
Equity-curve overlay	Change risk after drawdown or performance states	Testing adaptive exposure rules	Can react late, compound estimation noise and overfit the backtest

No method is automatically superior. A method that looks smoother can simply be using less exposure. A method that compounds faster in-sample can be overreacting to a favorable historical sequence.

Fixed Fractional Is a Convention, Not a Law

Under fixed fractional sizing:

Loss budget = selected account basis × selected fraction

CME Group describes the popular 2% rule but explicitly notes that the threshold is arbitrary and that traders can choose tighter or looser parameters. The percentage should therefore be treated as a versioned input, not as proof that the resulting position is safe.

A percentage test should disclose:

which account basis was used;
when the basis was updated;
whether open profit and loss was included;
whether costs and adverse fills were deducted from the budget;
whether overlapping positions shared one portfolio cap;
how minimum contract or lot size affected the result;
whether the strategy could lose more than the modeled stop amount.

The exact 1% rule discussion remains separate from this method-comparison page.

Volatility-Based Sizing Has Two Different Meanings

The phrase “volatility-adjusted position sizing” is often used for two different approaches.

1. Volatility-Distance Sizing

A volatility measure helps define or normalize the invalidation distance. Quantity is then solved from the loss budget.

Reference distance = volatility measure × documented multiplier
Quantity = loss budget ÷ converted reference loss per unit

This approach changes the denominator. A wider reference distance produces fewer units when the budget is unchanged.

The version must identify:

ATR, standard deviation, historical range or another measure;
lookback and smoothing method;
chart interval and session;
closed-bar or live value;
multiplier or percentile rule;
minimum and maximum distance handling;
stock-adjustment, futures-roll and data-provider settings.

The ATR measurement guide owns ATR calculation and data controls.

2. Portfolio Volatility Targeting

A portfolio model can size positions so each contributes toward a target volatility or risk allocation. This changes the portfolio exposure target rather than merely moving a chart stop.

It requires estimates of volatility and correlation, and possibly leverage constraints. Those estimates can change quickly in stress periods. It should not be described as the same method as “two ATR from entry.”

Kelly Criterion: What It Optimizes and What It Assumes

J. L. Kelly Jr.'s 1956 paper derived a fraction that maximizes the long-run exponential, or logarithmic, growth rate under a defined probability and payoff structure. In the simplified binary-bet form commonly adapted for trading:

f* = (b × p - q) ÷ b

Where:

p = estimated win probability;
q = 1 - p;
b = net payoff per unit lost;
f* = the resulting capital fraction under that simplified model.

The output is not automatically a “risk per trade” recommendation for a real trading strategy. The adaptation can fail when:

win probability and average payoff are estimated from a small or selected sample;
outcomes are not independent;
losses have fat tails or can exceed the modeled amount;
strategy parameters, costs or market regimes change;
positions overlap and share market exposure;
return distributions are not adequately represented by a binary win/loss model;
leverage, margin, liquidity and path constraints are ignored.

Fractional Kelly scales the model output down, but it does not repair incorrect inputs or an invalid payoff model. Research on risk-constrained Kelly formulations exists precisely because maximizing log growth and controlling drawdown risk are not identical objectives.

Use Kelly as a research model only after defining the return distribution, loss boundary, estimation window, costs, dependence and out-of-sample procedure. Do not take a large percentage from a short win-rate calculation and assume the result is safe.

Multiple Positions: Sum Risk, Then Examine Shared Drivers

Adding the standalone worksheet losses is a useful first step:

Gross planned portfolio loss
= sum of planned loss across open positions

But three positions with the same dollar budget do not necessarily contribute the same portfolio risk.

Review:

same-sector or same-industry exposure;
common index or market-beta exposure;
shared currency, duration, commodity or volatility factors;
simultaneous earnings, economic-release or event risk;
long and short positions that are not reliable hedges under stress;
liquidity that disappears at the same time;
option or leveraged positions with nonlinear losses;
margin increases or forced liquidation across the account.

The portfolio heat guide owns combined planned-risk monitoring. Correlation is not a fixed multiplier and should not be reduced to “three correlated trades equal one trade” without a documented model.

Scaling In Requires Recalculating the Entire Position

For a long position with multiple fills, calculate the weighted average entry:

Weighted entry
= sum(fill price × fill quantity) ÷ total quantity

Then recalculate the loss of every open unit against the current documented invalidation or exit rule. Do not assume an earlier open profit permanently offsets a new add-on. The market can gap, a stop can fill worse than planned, and different quantities can be partially filled.

Record each add-on as a state transition:

quantity before the add;
new fill price and quantity;
weighted entry after the add;
current invalidation reference;
protective-order quantity and activation state;
planned and stress loss after costs;
combined portfolio exposure;
reason the new quantity remains within the versioned rule.

Scaling out changes quantity and realized profit or loss, but it does not automatically make the remaining position “risk free.” The remaining units still have market, gap, operational and opportunity risk.

Common Calculation Failures

Confusing Fixed Fractional with Fixed Ratio

A formula that risks a constant percentage of current equity is fixed fractional sizing. Fixed-ratio methods use a different position-growth schedule. Labeling the method correctly matters when results are compared.

Dividing by Price Distance Without a Value Multiplier

A 20-point futures stop is not $20 per contract. A $0.85 standard equity-option premium move is not $0.85 per contract. Convert through the exchange or contract specification.

Using Margin as the Denominator

Margin answers how much collateral is required, not how much the position can lose at the modeled exit. Lower margin can increase accessible leverage without reducing price sensitivity.

Rounding to the Nearest Tradable Unit

Rounding up can exceed the budget. Round down unless the plan explicitly accepts the larger loss and records that decision before entry.

Ignoring Account Currency

A pip, point or profit/loss amount may be quoted in a currency different from the account. Convert with a documented rate and timestamp.

Treating the Stop as a Guaranteed Fill

The stop trigger and execution price can differ. Include normal and stress assumptions rather than presenting the budget as a hard cap.

Making the Stop Artificially Tight to Increase Quantity

The invalidation should come from the documented setup rule. Moving it closer only to obtain more units changes the trade definition and can invalidate the comparison.

Using Confidence as an Unmeasured Multiplier

“High conviction” is not a sizing model unless it is defined before the trade, supported by out-of-sample evidence, and applied consistently. Otherwise it can disguise discretionary overexposure.

Ignoring Minimum Units

One futures contract, one option strategy unit, or a broker's minimum forex/crypto increment may already exceed the budget. The correct result can be no position.

How to Test a Position Sizing Method

A sizing model should be compared on the same opportunities, not on a different collection of trades selected after seeing the result.

Step 1: Freeze the Base Strategy

Keep the following identical across sizing versions:

market and instrument universe;
entry and exit rules;
data source and session;
signal timing;
execution assumptions;
test dates and chronological order.

The position-sizing method should be the main variable.

Step 2: Freeze the Sizing Version

Record:

account basis and update time;
loss-budget rule;
distance or volatility rule;
unit-value source;
costs and adverse-fill assumptions;
quantity increment and rounding;
margin and leverage limits;
per-position and portfolio constraints;
gap, halt, assignment and liquidation treatment;
Kelly estimation window or other model inputs.

Step 3: Use Chronological Data

Sizing creates path dependence. A loss early in the sequence changes later fixed-fractional quantities. Randomly reordering trades can produce a different equity path even when the individual trade outcomes are unchanged.

Use chronological data and separate development, validation and prospective periods. Prevent future information from entering account equity, volatility, covariance, win-rate or payoff estimates.

Step 4: Include Tradable Constraints

Apply:

whole-contract or lot rounding;
fractional-share availability;
minimum order values;
broker and exchange limits;
cash and margin checks;
costs, spread and slippage;
financing, borrow and funding where relevant;
partial-fill and no-fill rules;
multi-currency conversion.

A model that relies on impossible fractional futures contracts or ignores margin calls is not an executable comparison.

Step 5: Compare More Than Ending Equity

Useful outputs include:

ending equity and geometric growth;
maximum and duration of drawdown;
recovery time;
return and loss concentration;
largest position and largest factor exposure;
turnover and total costs;
margin utilization and forced-liquidation events;
percentage of opportunities skipped because of minimum size or constraints;
sensitivity to worse fills and gap scenarios;
out-of-sample stability across nearby parameters.

A higher return created only by more exposure is not evidence of a better sizing rule.

Step 6: Use Baselines and Rejection Rules

Compare against simple baselines such as:

one fixed unit;
fixed notional allocation;
fixed dollar loss budget;
one conservative fixed-fractional version;
no leverage;
buy-and-hold or cash where relevant to the research question.

Predefine reasons to reject a method, such as dependence on one extreme trade, excessive concentration, unrealistic margin, unstable nearby parameters, failure after costs, or poor out-of-sample behavior.

For the broader research process, use the procedural backtesting guide.

A Position Sizing Worksheet

Field	Record before entry
Instrument and exact contract	Symbol, exchange/venue, expiry or contract version
Account basis	Value, currency and timestamp
Loss-budget rule	Fixed dollar, fixed fraction or model output
Entry assumption	Price and order/timing rule
Invalidation reference	Chart or strategy rule, separate from the broker order
Unit conversion	Share value, tick/point value, pip value, multiplier or inverse-contract rule
Costs	Commission, spread, fees, financing and estimated slippage
Adverse-fill allowance	Explicit ticks, pips, percentage or scenario
Raw quantity	Budget divided by planned loss per unit
Rounded quantity	Tradable increment after rounding down
Notional and margin	Separate operational checks
Existing exposure	Sector, factor, currency, strategy and correlated positions
Stress loss	Gap, halt, assignment, liquidation or unavailable-exit scenario
No-trade reason	Minimum unit, excessive concentration, unavailable data or failed constraint
Version ID	Rule set used for later review

This record makes the calculation auditable. It also prevents a favorable outcome from retroactively turning an unplanned size into a “good decision.”

What ChartMini Can and Cannot Test

ChartMini can replay historical candles while hiding future bars. That can support a chart-first exercise:

pause before revealing future candles;
define a hypothetical entry and invalidation from the chart;
record a hypothetical account basis and loss budget;
obtain the instrument specification from an appropriate external source;
calculate and round a hypothetical quantity in a separate worksheet;
reveal the next candles and record the chart path;
compare sizing versions on the same chronological examples.

ChartMini does not:

connect to a live brokerage account;
calculate an optimal or personalized risk fraction;
retrieve current futures, options, forex or crypto contract specifications;
calculate live pip, tick, point, multiplier or currency-conversion values;
verify cash, buying power, house margin or liquidation rules;
reproduce spread, depth, queue position, partial fills or broker execution;
model option Greeks, early assignment, expiration or multi-leg execution;
monitor open positions, portfolio heat or correlated exposure;
send risk alerts or guarantee that a worksheet matches live trading.

Candle replay can test decision timing and process consistency. It cannot certify a position size for real-money execution.

Frequently Asked Questions

What is position sizing in trading?

Position sizing is the process of converting a predeclared loss budget into a tradable quantity, such as shares, contracts, lots, or coins. A complete calculation also checks the instrument's value per price unit, fees, spread, adverse fills, quantity increments, margin, buying power, and combined portfolio exposure.

What is the position sizing formula?

A general formula is quantity equals risk budget divided by planned loss per tradable unit, rounded down to an allowed increment. Planned loss per unit should include the entry-to-invalidation distance converted through the correct share, tick, point, pip, contract, or currency value, plus estimated costs and an adverse-fill allowance.

Is 1% risk per trade a universal rule?

No. One percent and two percent are conventions, not laws. The selected loss budget depends on the account basis, strategy evidence, drawdown tolerance, instrument granularity, leverage, liquidity, gap exposure, correlated positions, and the possibility that actual execution differs from the planned exit.

How do you size futures and options correctly?

For futures, convert the stop distance through the exchange-listed point value or tick value and round down to whole contracts. For options, verify the contract multiplier and strategy-specific loss profile; standard U.S. equity options commonly represent 100 shares, but adjusted and other option products can differ. Margin or premium alone is not a universal measure of planned loss.

Can a stop loss guarantee the planned loss?

No. A stop price is a trigger, not a guaranteed execution price. A stop order normally becomes a market order after the trigger and can fill materially away from the stop during gaps, fast markets, thin liquidity, halts, or other disruptions. A sizing worksheet should therefore distinguish planned stop risk from adverse-fill and gap scenarios.

Can ChartMini calculate live position size?

No. ChartMini replays historical candles for chart-decision practice. It does not read a live brokerage account, retrieve current contract specifications, calculate pip or tick values, model option assignment, verify margin, reproduce order-book liquidity, simulate broker fills, monitor portfolio heat, or send risk-limit alerts.

Sources and Further Reading

Position sizing does not make an unprofitable strategy profitable and does not guarantee that a loss remains inside the worksheet budget. Its purpose is to make the exposure rule explicit, instrument-aware, testable and reviewable before the outcome is known.

Position Sizing Methods: Fixed Risk, Volatility, and Kelly