Irish racing tycoons John Magnier and JP McManus have built a 3.4 % stake in All Bar One and O'Neil's operator Mitchells & Butler through an investment group called Elpida.
The stake, worth £84m, does not come close to the 14% held by Robert Tchenguiz, who was forced to abandon a £4.5b property joint venture with the operator back in September.
According to the Financial Times, the two investors said they viewed M&B as a "value investment with great potential".
Magnier and McManus rose to prominence as the built a 28.7% share in Manchester United before it was sold to US businessman Malcolm Glazer in 2005 for a sizeable profit.
M&B's shares have performed poorly since the collapse of the Tchenguiz joint venture, falling by 21% in three months.
By Christopher Walton
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