Considering that there are still 14561.94104029 BTC on source address, 250btc is a small number for this person.
Edit:
I thought maybe it could be a shared web wallet, mtgox type, but I would say no.
curiosity:https://blockchain.info/related_tags?active=1Fx3N5iFPDQxUKhhmDJqCMmi3U8Y7gSncx
This is the MPEx Exchange address (1Fx3N5iFPDQxUKhhmDJqCMmi3U8Y7gSncx). So is this betting with customers exchange funds, or the bookkeeper betting against his own customers (Mircea Popescu partially owns BitBet)?