The London Stock Exchange said on Monday that it had cancelled all Polymetal trades executed between 0841 GMT and 0902 GMT after a spike in shares of the Anglo-Russian precious metals miner.
The LSE had said in a notice to members earlier that it was investigating trades in Polymetal after the shares surged 700% and that some of them could be cancelled.
At 1055 GMT, the shares were up 31% at 223.11p, having jumped to as high as 1,400p earlier in the morning.
