A US legislative plan to regulate the near-$600,000bn market in over-the-counter derivatives suggests lawmakers debate the idea of banning so-called “naked credit default swaps”, which allow investors to speculate on the creditworthiness of companies.

The proposal by key committees of the House of Representatives would push most derivatives on to an exchange or clearing house but leaves open the issue of whether to outlaw CDSs – a type of insurance against bonds defaulting – in which the buyer does not own the underlying asset.