WHAT COULD GO WRONG? Citi Is Bringing Back One of the Most Infamous Bets of the Credit Crisis.

It’s an astonishing comeback for the roughly $70 billion market for synthetic CDOs, which rose to infamy during the crisis and then faded into obscurity after nearly destroying the financial system. But perhaps the most surprising twist is Citigroup itself. Less than a decade ago, the bank was forced into a taxpayer bailout after suffering huge losses on similar types of securities tied to mortgages. Now, many in the industry say Citigroup is responsible for over half the deals that come to market, though precise numbers are hard to come by.

This time, Citigroup says, it’s doing things differently. The deals are tailored in a way that insulates it from any losses, while giving yield-starved buyers a chance to reap returns of 20 percent or more. The market today is also just a fraction of its size before the crisis, and few see corporate defaults surging any time soon. But as years of rock-bottom interest rates have pushed investors toward riskier products, the revival of synthetic CDOs may be one of the clearest signs yet of froth in the credit markets.

I have a bad feeling about this…