Investments banks are the biggest buyers and sellers of credit derivatives, which could come back to haunt them if a debt crisis occurs as people fear, according to a new survey.

Fitch Ratings' global credit derivatives survey of 65 banks and insurers found that the total amount of credit derivatives bought and sold reached nearly $50 trillion (€36 trillion) at the end of 2006, more than double the previous year when $23.4 trillion of derivatives were traded. It also represents a tenfold increase from the volumes of credit derivatives bought and sold in 2003, when Fitch first started the survey.