Two sets of figures, one I was part of a hedge fund, one was trading individually.
Hedge fund, best day, Up about $6.2M, the day that QCOM and YHOO went nuts in 1999. In one day, QCOM holding went from around 5% of the fund to 8% of the fund, insane. I remember that day well, I made 60% of my bonus for the year that day.
Worst day, down about $2.5M, was doing simple merger arb (forgot which), and the government leaked out they were against the deal.
Personally, best day, up about $150k, trading futures, every trade the system made was right, insane, I wasn't even trading size, was experimenting with a new system.
Worst day, in memory anyways, down about $90k, actually not that bad, was down bout 160k then the system naturally recovered, it wasn't even a number / event day.
Rufus
Quote from Rearden Metal:
Best day: Up $438,000
Worst day: Down $1,500,000 (After recovering from being down 2 1/2 mil on the day.