A negative transaction cost indicates that transacting has resulted in a net revenue rather than a net cost for the fund. This can happen for two main reasons:
- The amount of money a fund obtains from its Swing Pricing mechanism offsets most or all of the transaction costs that the fund incurs.
- If a stock is taking a number of hours to sell/buy, the price can rise/fall in the time between placing the order and execution, so it exceeds/falls below the original arrival price and therefore offsets other transaction costs.
If this happens to enough trades, an overall negative transaction cost can accrue.