Fill Settings

Updated Sep 16, 2026

The following settings are available for every backtest position to control brokerage fees and slippage.

Broker Fee

This is the fee that you will spend per contract that is opened or closed.

Price for Zero-Fee BTC

Some brokers waive fees if you buy-to-close (BTC) a position below a certain premium. If this applies to you, you can specify that premium cutoff here, and the backtester will not include fees when you BTC at that price or lower.

Assignment/Exercise Fee

If you hold a position in-the-money at expiration and need to apply a fee to that position, you can do that with this setting. This will apply the fee that you specify to each in-the-money leg that is held to expiration, regardless of the number of contracts.

Fill Model

Two ways to price your entry fills:

• Dynamic — entries fill at what orders of that kind actually filled at on Whispertrades: real execution data grouped by symbol, position type, order type, days to expiration, time of day and spread width. This is recommended for most backtests.

• Flat — every entry fills at the entry slippage percentage you set in the next fields. Useful if you are doing specific study/research on slippage or spread widths.

A few things worth knowing about Dynamic:

• It is deterministic. The same backtest gives the same result every time; nothing is randomized. As new order data is collected, fill prices and results can change.

• Where real execution data for that kind of order is too thin to be meaningful, it falls back to your flat entry percentage rather than guessing from a handful of fills.

• The data behind it is aggregated across the platform, never from a single member's trading.

Minutes Between Trades

Number of minutes to insert between trades. This determines how many minutes to place between the exit of one trade and the entry of the next (for Sequential trade entries). You should enter a value here that most closely represents how quickly you can cycle into a new trade. If you have automated this trade, your time between trades may be just 1 minute. However, if you are manually trading, you may find this should be 30 minutes to reflect your availability to enter a new trade during the day.