Reply #1: Additionally, I have trouble believing that the software requires the trader to type "millions" [View All]

I've worked with four different trading platforms (admittedly, there are countless variations, so the four I've seen might not represent anything like the norm) and all of them required pure numeric inputs. That is, a five million dollar trade is entered as 5000000.00, while a five billion dollar trade would be 5000000000.00.

Incidentally, the largest single trade that I ever processed was for $750M, followed by $250M for the same client--it was a billion-dollar transaction, but the system couldn't handle trades that large, so we had to break it into to pieces. Whatever system the "fat-fingered" guy was using, I suspect that it would issue a warning for trades entered in that huge amount, if it would let them be processed at all.

If a typo did indeed occur along these lines, it seems almost more likely that he mistyped/miswrote an email to the person who actually placed the trade.

Of course, that would mean that there are at least two idiots who need to be fired, but that's how it goes.