Shares in French steakhouse chain Buffalo Grill soared on Monday on rumours that its owners are ready to sell the group if the right offer comes in. The group suffered a serious decline in custom late last year when it was suspected of violating the embargo on British beef. Chairman, Christian Picart, who along with his family controls almost 75% of the group, has denied media reports that Buffalo Grill has been in sale negotiations with a leading French retailer since the start of the year.