Fidelity roundtrip transaction似乎只定义了1次transaction。
"We monitor the number of roundtrip transactions in shareholder accounts. A roundtrip is a mutual fund purchase or exchange purchase followed by a sell or exchange sell within 30 calendar days in the same fund and account. For example, if you purchased a fund on May 1, selling the fund prior to May 31 would incur a roundtrip violation. It is important to remember that share aging FIFO (First In First Out) is not considered when buy and sell transactions are evaluated for roundtrips.
Certain transactions are exempt from roundtrip violations. These include:
Trades for $1,000 or less. (Please note that if more than one buy order or sell order for a given fund is executed on the same day in the same account, the $1,000 threshold is based on the total dollar value of all orders for that fund.)
Any transactions in Fidelity Money Market Funds
Dividend and capital gains reinvestments that are sold within 30 days
Orders placed via Fidelity Automatic Investments or Automatic Withdrawals features“