JP McManus and John Magnier, the Irish investors, are thought to have again increased their stake in Mitchells & Butlers (M&B), the pub and casual dining group. Reports suggest the duo, through their Elpida Group investment vehicle, were involved in stakebuilding yesterday after two blocks of five million shares – about 2.5% of the group – changed hands. Elpida currently appears on the M&B share register with just over 6%. A further 10 million shares would take it to 8.53%. The market rumours emerged a day after Robert Tchenguiz upped his stake to 27%, with observers speculating that both parties could be seeking to block private equity firms from taking big stakes in new shares. M&B will announce the results of a strategic review on May 20. M&B rose 3.5p to 344p against a pub market that was down after the excitement provoked of Real Estate Investment Trusts – when Enterprise announced it could adopt the tax-efficient structure. Enterprise came back 11p to 499p, Marston’s fell 9.25p to 225.75p and Greene King dropped 5.5p to 585p.