KPMG Peat Marwick, the US professional services firm, is to be questioned by the Securities and Exchange Commission, the senior US financial regulator, over its announcement that it may float part of the partnership.

Ms Lynn Turner, the newly installed chief accountant at the SEC, said in a rare public statement that the firm's decision to explore an initial public offering or a sale to a private investor raised issues of auditor independence that must be addressed.

Mr Steve Butler, the US firm's chief executive, announced last month that it was considering offering 30 per cent of its consultancy business for sale.

Annual revenues for the business, announced yesterday, are $1.5 billion (£1.01 billion) a year.

Mr Butler's decision to appoint investment bankers to look at options, including a public offering, is being keenly followed by other "Big Five" professional services firms in the US and overseas and by other member firms of KPMG.

Several other firms have considered a similar flotation.

"We are obviously in discussions with the SEC about this initiative," said Mr George Ledwith, spokesman for KPMG Peat Marwick in New York.

He said the firm was still at an early stage in considering its options.

KPMG Peat Marwick, part of the global KPMG network, is one of the five largest auditors of public companies in the US.

It audits five of the 25 largest US-based multinationals: General Electric, Citicorp, Motorola, Xerox, and PepsiCo.

It has overall revenues of $3.8 billion.