Private equity companies, including TPG, value investors such as Wilbur Ross and asset management firms are considering launching bond insurers in a move that could hamper efforts to aid troubled incumbents such as Ambac and MBIA.

Private equity executives say that, at a time when total exposure is impossible to calculate, it is far more attractive to start a new enterprise than to invest in existing firms. They note that the credit turmoil has hit existing providers, premiums are high and regulators are keen to stabilise the market.