BlackRock (BLK.N) has hired a senior executive from communications and investor relations firm Joele Frank to lead its investment stewardship team in the Americas, which oversees the asset manager’s interactions with hundreds of U.S. companies.

John Roe will join as managing director, head of BlackRock Investment Stewardship (BIS), Americas, next week, according to a memo sent to employees on Monday and seen by Reuters.

BlackRock oversees $9.5 trillion in assets and already has one of the most powerful voices in the governance world, as it is large owner in most companies. It also has recently signaled it is taking a much tougher stance on climate and sustainability issues.

Roe will replace Ray Cameron, who for three years headed investment stewardship for the Americas and moved to BlackRock’s institutional client business several weeks ago. The investment stewardship team in the United States has seen some turnover with a number of people leaving recently.

Roe co-led the ESG (environmental, social and governance) Group as a partner at Joele Frank and previously worked at prominent proxy advisory firm Institutional Shareholder Services (ISS), where he was head of ISS Analytics. Before that he worked as chief operating officer at an equity investment fund.

“John therefore joins us with a blend of governance experience gained from his time on the buy side, in a leadership role at a proxy advisor firm, and his most recent role at Joele Frank,” Sandy Boss, BlackRock’s global head of investment stewardship, wrote in the memo.

As its assets swell, BlackRock, one of the world’s biggest asset managers, has become increasingly influential in guiding corporate behavior.

Every year BlackRock and peers such as Vanguard Group and State Street Group vote on critical corporate issues like lobbying disclosures and a company’s stance on climate change, and can help decide who sits on a company’s board.