i had my first ever fat finger. I was gonna close to lock in my profits yesterday on 14 short call contracts I sold but somehow I accidentally sold to open 14 not buy to close I did a quick review and saw -28 contracts and I was oh shit I closed them out but it cost me 600 bucks out of my profit. Lol. Still made a profit but minus 600 for the error since the markets were moving and the bid ask spread got wide Anyhow glad I quickly double checked instead of leaving and assuming the trading day was over in the afternoon. Dumb mistake, first time ever.
Sounds like an execution error more so than a fat finger.. A fat finger is like you add an extra digit to the order size because you mashed the keypad while writing up your ticket.
Been there done that! :-( I have had many forms of that as well.... Allocated trade orders in TOS often mix up the quantities in accounts, causing some trepidation.