BOSTON (Reuters) - State Street Corp STT.N wants answers from companies that lack such things as independent board leaders or equal voting rights for investors, a top executive at the asset manager said, which could spell weaker support for some companies whose shares it controls.

The logo and trading symbol of financial services company State Street are displayed on a screen on the floor of the New York Stock Exchange (NYSE) in New York, U.S., March 8, 2017. REUTERS/Brendan McDermid

Boston-based State Street and other top fund firms last year adopted a set of good-corporate-governance principles meant to improve oversight at companies whose shares they hold.

“We’re going to be asking companies to explain either their compliance or exceptions” from the new principles, Rakhi Kumar, head of asset stewardship for State Street’s asset-management arm, said in a telephone interview late on Thursday.

State Street had $2.8 trillion under management as of Dec 31.

Companies that cannot adequately explain their structures can expect votes against management’s recommendations, according to a recent State Street memo sent to corporate directors.

Fund firms are worried by the rise of corporate structures that concentrate power with insiders, such as last year's initial public offering by Snap Inc SNAP.N that included no voting rights for outside investors.

Critics have said the asset managers could do more to enforce their governance concerns, such as refusing to buy the shares.

Kumar said that is not always possible for State Street’s index funds, but the burden will be on company leaders. “We want to make sure that you’re shareholder friendly and you’re putting thought into governance,” she said.

State Street and rivals BlackRock Inc BLK.N and Vanguard Group have emerged as dominant shareholders of most publicly traded U.S. companies, as investors pour billions into the firms' passive investment strategies.

The firms in turn have emphasized environmental, social and governance concerns to attract investor assets. State Street has recently pressed gun makers for safety details after last month’s high school shooting in Florida, and last year placed the “Fearless Girl” statue near Wall Street to highlight its efforts to promote gender diversity.

But filings later showed State Street funds abstained on some shareholder resolutions focused on boardroom diversity. Kumar said it was too soon to provide new details about talks with gun makers and she declined to discuss votes or outreach at specific companies.

But she said State Street may cast “abstain” proxy votes more often this year to signal its unhappiness with management. Such votes will give State Street a way to convey nuance, she said, whereas before it might have backed management but “with a heavy heart.”