You are right, I got nailed by the IRS on this. I trade Forex and made about 15K 2 years ago. Now the offshore broker of course does not report profits to the IRS. I stupidly wired the whole 15K in one shot into my bank account and didn't tell Uncle Sam.
Then a I got nice letter from the IRS asking about the deposit, and to provide an explanation. I ended up having to pay 40% taxes on that!
Had I just wired in $7500 one day, and $7500 the next they would have been none the wiser...
And people don't think they can trace the 4.4 Billion? lol. JPM is really reaching here...