Top US securitisation practice Sidley Austin has secured a high-profile instruction to advise alongside rival Mayer Brown on the cutting-edge $80bn (£38bn) 'superfund' designed to restore confidence in the credit markets, as firms look to secure roles on the process.

The fund, created by Citi, Bank of America and JP Morgan Chase, was announced at the end of last month and aims to halt a further drop in market prices by offering to buy assets from structured investment vehicles (SIVs), helping them to avoid dumping securities.

Sidley was brought in to advise the structuring banks on US issues alongside Mayer Brown securitisation partner Jason Kravitt last week. Allen & Overy, led by capital markets partner Geoff Fuller, is advising the banks on UK issues.

Elsewhere, Cleary Gottlieb Steen & Hamilton, led by New York finance partner David Sugerman, is advising the liquidity banks, which will include the structuring banks and a panel of up to 30 banks brought in to inject funds. Wachovia, Dresdner Kleinwort, Merrill Lynch and Lehman Brothers are reported to have expressed an interest in getting involved.

Firms, including Clifford Chance and Linklaters, which advise SIVs, will be in prime position to benefit from dealings with the fund if it proves successful. However, the process could take months to get off the ground and it is currently unclear how it will work.

Finance lawyers have questioned how the price of assets to be bought by the fund will be assessed. One partner said: "The assets an SIV owns would normally have a price determined by the market, but recently there has not been a market for asset-backed securities."