Three of Canada’s largest pension funds sold a combined 10 percent stake in TMX Group Ltd. for about C$312 million ($241 million), cutting by almost half their holdings in the operator of the Toronto Stock Exchange. Alberta Investment Management Corp., on behalf of some of its clients, Caisse de Depot et Placement du Quebec and Ontario Teachers’ Pension Plan Board each agreed to sell 1.8 million common shares of TMX at C$57.70 a share through a group of banks led by Toronto-Dominion Bank’s TD Securities, according to a joint statement Monday.