BlackRock Investments Canada, the asset manager, has announced that Som Seif, former president and chief executive of Claymore Investments, will be leaving the company to pursue other opportunities. Seif, head of the ETF business BlackRock announced plans to acquire in January, will remain at BlackRock until mid-April to support the transition. In this capacity, he will be working with Mary Anne Wiley, managing director, in her role as head of the combined ETF business.