Mitt Romney is indisputably a very rich man. And if he is elected president on Nov. 6, he will become one of the wealthiest people ever to hold the office.

But exactly how wealthy is Romney? The figure that gets tossed around is $250 million in net worth — meaning the total value of his assets, financial and others, minus any debts.

It’s a big number, but frankly, it seems low. Given the industry in which he made his fortune ( private equity), the era when he made it (the 1980s and 1990s) and the wealth of his peers in that business (mostly billionaires), Romney should be worth a good bit more than that.

Why isn’t he?