(Reuters) - Mark Wiseman, global head of active equities at BlackRock Inc BLK.N, is leaving the firm following a violation of the company's "relationships at work policy," the world's largest asset manager said in an internal memo on Thursday.

Mark Wiseman, Global Head of Active Equities and Chairman of BlackRock Alternative Investors at BlackRock LLC, speaks during the Reuters Global Investment Outlook Summit in New York, U.S., November 16, 2017. REUTERS/Mike Segar

Wiseman, one of several people tipped as BlackRock Chief Executive Larry Fink’s possible successors, is a former Canadian pension manager who ran active equities and served as chairman of the $7 trillion indexing behemoth’s alternatives unit.

“When the firm becomes aware of a breach of policy or conduct that is not in line with our values, we move quickly and decisively to address it,” Fink and BlackRock President Rob Kapito said in the memo, which was reviewed by Reuters.

Fink, one of BlackRock’s founders in 1988, has not publicly named a successor or announced any plans to retire, but Wiseman was one of a handful of executives analysts have pointed to as a potential successor.

In a separate memo to employees, Wiseman said, “I am leaving BlackRock because in recent months I engaged in a consensual relationship with one of our colleagues without reporting it as required by BlackRock’s Relationships at Work Policy. I regret my mistake and I accept responsibility for my actions.”

Wiseman’s conduct had no impact on any portfolios or client activities, the first memo said. BlackRock’s active equity unit had about $290 billion in assets at the end of June.

The leaders of the active equity teams who previously reported to Wiseman will now report to Kapito, the company said.

“Mark was a high-profile addition to BlackRock with a distinguished background but BlackRock has a deep bench and a very strong leadership team,” Gabelli & Co analyst Macrae Sykes said.

BlackRock hired Wiseman and his wife Marcia Moffat in recent years. Wiseman joined in May 2016 from the Canada Pension Plan Investment Board, where he served as chief executive, while Moffat joined BlackRock from RBC in July 2015 to head the asset manager’s Canadian operations.

The relationship that Wiseman failed to disclose was with a different BlackRock employee, the Wall Street Journal said on Thursday, citing an unidentified person familiar with the matter. The Financial Times also reported his departure earlier in the day.

Wiseman is the second BlackRock senior executive to leave this year due to lapses in personal conduct. Jeff Smith, head of the human resources group at BlackRock, left in July because “he failed to adhere to company policy,” BlackRock said at the time.

Earlier this year, BlackRock made several changes to its senior leadership ranks aimed at winning more business and boosting growth of its alternative investing business.

BlackRock declined to comment beyond the contents of the memo.

BlackRock shares, up about 24% this year, were 0.8% higher at $487.44 in morning trade on Thursday.