"Mr. Systrom was just hours from signing a deal for a $50 million venture-capital investment that would put a $500 million value on his company" So this started before the deal was closed. Did the funding round close?
Yes, the round closed the day before the acquisition, iirc.
funny that they would only need to let their investment ride into equivalent investments for another 21 days before reaching a return of 209 Trillion dollars, which is in excess of the total value of all stocks, bonds and currency in the world.
[1] http://www.wolframalpha.com/input/?i=%3D+%281+billion+-+500+...