Position Sizing Modes: Fixed Quantity vs Multiplier

Position sizing determines how many contracts a follower account trades when the leader places an order. MimikTrader offers two sizing modes, each suited to different use cases. The sizing mode is configured per follower account on the Risk Management page, so different followers in the same copy group can use different sizing strategies.

Fixed Quantity Mode

In fixed quantity mode, the follower trades the same number of contracts on every opening trade, regardless of how many contracts the leader trades. The quantity used is the max contracts value configured on the follower's risk profile.

This mode is ideal when:

• You want absolute consistency in position size across all trades.
• Your prop firm has strict position size rules that require a fixed number of contracts per trade.
• The leader varies their position size based on conviction or market conditions, but you want your follower to trade a constant amount.

Fixed Quantity Examples

With max contracts set to 2 in fixed quantity mode:

• Leader buys 1 NQ → Follower buys 2 NQ
• Leader buys 3 NQ → Follower buys 2 NQ
• Leader buys 10 NQ → Follower buys 2 NQ
• Leader buys 50 NQ → Follower buys 2 NQ

The leader's quantity is completely ignored for opening trades. The follower always enters with exactly the configured amount.

Multiplier Mode

In multiplier mode, the follower's quantity is calculated by multiplying the leader's trade size by a configurable multiplier. The result is rounded to the nearest whole number (since you cannot trade fractional contracts) and then clamped between 1 and the max contracts value.

The formula: clamp(Math.round(leaderQty × multiplier), 1, maxContracts)

Multiplier Examples

With multiplier set to 1.0 and max contracts set to 10:

• Leader buys 1 → round(1 × 1.0) = 1 → Follower buys 1
• Leader buys 5 → round(5 × 1.0) = 5 → Follower buys 5
• Leader buys 15 → round(15 × 1.0) = 15, clamped to 10 → Follower buys 10

With multiplier set to 0.5 and max contracts set to 5:

• Leader buys 2 → round(2 × 0.5) = 1 → Follower buys 1
• Leader buys 4 → round(4 × 0.5) = 2 → Follower buys 2
• Leader buys 6 → round(6 × 0.5) = 3 → Follower buys 3
• Leader buys 20 → round(20 × 0.5) = 10, clamped to 5 → Follower buys 5

With multiplier set to 2.0 and max contracts set to 8:

• Leader buys 1 → round(1 × 2.0) = 2 → Follower buys 2
• Leader buys 3 → round(3 × 2.0) = 6 → Follower buys 6
• Leader buys 5 → round(5 × 2.0) = 10, clamped to 8 → Follower buys 8

Rounding Behavior

MimikTrader uses standard mathematical rounding (Math.round) when calculating the multiplier result. This means 0.5 rounds up to 1, 1.4 rounds down to 1, and 1.5 rounds up to 2. The minimum result is always 1 — if the calculation produces zero or a negative number (which would only happen with extremely small multipliers), the floor of 1 contract is applied.

How Sizing Interacts with Close Operations

The sizing mode only applies to opening and adding trades. When the leader closes or reduces a position, MimikTrader uses proportional ratio math instead of the sizing mode. This is a critical distinction:

Proportional Close Ratio

When the leader reduces their position (but is not yet flat), MimikTrader calculates what percentage of the leader's position was closed, then applies that same percentage to the follower's position. The formula is: followerCloseQty = round(followerPosition × (leaderCloseQty / leaderPosition))

For example:

• Leader has 6 contracts, closes 2 (33%) → Follower has 3 contracts, closes round(3 × 0.33) = 1 contract.
• Leader has 10 contracts, closes 5 (50%) → Follower has 4 contracts, closes round(4 × 0.50) = 2 contracts.
• Leader has 3 contracts, closes 1 (33%) → Follower has 1 contract, closes round(1 × 0.33) = 0, floored to 1 → Follower closes 1 (full close).

Full Close (Leader Goes Flat)

When the leader's position reaches zero (completely flat), MimikTrader closes all of the follower's remaining contracts. No proportional math is needed — the entire position is liquidated to ensure the follower matches the leader's flat state.

Choosing the Right Mode

Here is a quick guide for selecting the appropriate sizing mode:

• Use Fixed Quantity when: You want predictable, constant position sizes. Ideal for prop firm accounts with strict per-trade rules or when the leader's size variation is irrelevant to your strategy.
• Use Multiplier (1.0) when: You want to mirror the leader's exact trade sizes. This is the default "equal size" behavior — the follower trades the same number of contracts as the leader, up to the max contracts cap.
• Use Multiplier (<1.0) when: You want the follower to trade a fraction of the leader's size. Common when the follower has a smaller account or tighter drawdown limits.
• Use Multiplier (>1.0) when: You want the follower to trade a larger size than the leader. Common when combining cross-contract copying (micro contracts) with a multiplier to achieve similar dollar exposure.