(Bloomberg) -- Mary Anne Wiley left her position as managing director and head of iShares Canada, the exchange- traded funds unit of BlackRock Inc., as competitors encroach on the company’s leading market share.

Wiley told management earlier this year she planned to leave and departed the company last week, said Maeve Hannigan, a spokeswoman for iShares Canada. Warren Collier, chief operating officer for U.S. iShares, is replacing Wiley as acting head while the firm seeks a successor, Hannigan said in an interview today.

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