Sir Martin Sorrell, the advertising mogul, has received a number of merger approaches for S4 Capital, the London-listed marketing services group he founded seven years ago.

Sky News can reveal that Sir Martin has been contacted in recent weeks by potential suitors including One Equity Partners, a US-based private equity firm which focuses on acquiring companies in the healthcare, industrials, and technology sectors.

This weekend, analysts suggested that One Equity would seek to combine S4 Capital with MSQ, a creative and technology agency group it bought in 2023.

Further details of the possible tie-up were unclear on Saturday, including whether a formal proposal had been made or whether S4 Capital might remain listed on the London Stock Exchange if a deal were to be completed.

S4 Capital is also understood to have attracted recent interest from other parties, the identities of which could not be immediately established.

In March 2024, the Wall Street Journal reported that Sir Martin had rebuffed several offers from Stagwell, an advertising group led by Mark Penn, a former adviser to President Bill Clinton.

New Mountain Capital, another American private equity firm, was also said at the time to have held talks about buying parts or all of S4 Capital.