RJB said it had received a preliminary approach and that talks were at an "exploratory stage".
Reuters said it had received a "preliminary approach" but would not identify the bidder.
A subject of regular takeover speculation, the group has confirmed that its latest suitor had made a "very preliminary approach".
Without naming the bidder, Manchester United said that it had received a "preliminary approach regarding a possible offer".
Just last week, Chubb acknowledged it had "received a preliminary approach, which may or may not lead to an offer," after the company's stock jumped without explanation.
Jefferson Smurfit's panel of independent directors confirmed today that the company had received a preliminary approach from another bidder last month.
Malcolm Glazer, believed to be behind a preliminary approach to take control of Manchester United, is currently presiding over one of the worst teams in American football.
Accordingly, on March 30th Texas Pacific Group (TPG), a ravenous private-equity firm, made a preliminary approach to buy Iberia, Spain's leading airline, for €3.60 ($4.80) per share.
William Hill confirmed it had received a highly preliminary approach but that the consortium did not put forward a proposal on price, timing, terms, form of consideration or transaction structure.
Meanwhile Vodafone confirmed long standing, and growing, speculation that it was interested in Kabel Deutschland, saying it had made a preliminary approach but there was no guarantee an offer would be made.
Lower down the market silicon wafer specialist Pure Wafer jumped 1.5p to 6.5p as it announced it had received a preliminary approach for the company, but document management group Invu dropped 1.75p to 3.5p after it issued a profit warning.
