IBP's $3.2bn bid for by Tyson Foods may be delayed after the US Securities and Exchange Commission (SEC) sought clarification about some of IBP's past financial information and filings.

Tyson said on Thursday it was delaying the completion of its cash tender offer, as well as the filing of its exchange offer documents with the SEC, because questions had been raised. It added that it would "carefully monitor this situation to determine what impact, if any, the resolution of [the SEC's] questions related to past accounting practices will have on the financial statements and business".

IBP disclosed that the SEC's requests had been prompted by a proxy statement filed in November, when it was considering taking itself private via an offer backed by an investment bank.  Regulators are also seeking clarification on financial information from recent acquisitions.

Shares in IBP, the biggest beef processing and meatpacking business, tumbled US$3.25 in New York trading to US$25.37 - far below the US$30 a share Tyson is offering. Tyson nudged 12 cents higher to US$12.75. The deal still requires clearance from US anti-trust regulators