The same thing sprang to my mind, but Groupon did hit $17.8B at its IPO. Any significant shareholders who cashed out then would have made off like bandits.
You can't always depend on market irrationality, though.
VC firms became quite frantic during the market meltdown of 2008-2009. If a startup was burning cash, they told them to fire most of their staff. There was simply no exit possible -- either via IPO, or a sale to a larger company.