"People actually shouldn't be surprised there is a big number when you're adding up the costs of what's happened to this country," said Dennis Kelleher, chief executive officer of Better Markets, which advocates for tougher finance regulations and came up with the price for the economic collapse.
"Wall Street and its many allies and sympathizers are denying and understating the cost of the crisis to kill, weaken and avoid regulation," Kelleher said.
The San Jose (Calif.) Mercury News reported Thursday that Better Markets considers the price tag of the downturn a conservative estimate, because it does not include the cost of company bailouts, such as the $182.3 billion cost of bailing out American International Group, which eventually earned the Treasury Department about $15.1 billion in fees and dividends.
The calculation also does not include the hit home equity prices took.
Kelleher said the number was unarguably large.
"If you don't think it's $12.8 trillion, what do you think it is? If we're off by half, you're at $6.4 trillion -- and we're not off by half," he said.