Reads like a recruitment piece for programmers, or maybe that's how I read too many articles being programmer. I was a little confused by this:

> For example, Jane Street, which is privately held, has increased its shareholder’s equity, or net worth, to more than $1 billion today from $228 million in 2007.

Is this supposed to be an impressive stat? ZocDoc has become about $2 billion company in basically the same time frame, which seems more impressive given that ZocDoc didn't start from that $228M handicap. My perception is that it's also much more expensive to run a company like Jane Street.