WASHINGTON — The Securities and Exchange Commission yesterday voted 4 to 1 to approve a series of changes to its Rule 2a-7 on money market funds aimed at boosting the resilience of funds during market crises, and promised to move forward with additional rules in the future.

The SEC also voted 3 to 2 to issue interpretive guidance requiring companies to weigh whether legislative, regulatory, or other actions related to climate change would require them to make certain disclosures in corporate filings with the SEC.

The agency approved the measure only after a heated and unusual politically charged debate between Democratic and Republican commissioners on the existence of climate change. However, the guidance drew support from several large investors, including state governments.

Some portfolio managers applauded the money market rule changes, saying they will improve transparency, credit quality, and liquidity. The Investment Company Institute also supported the proposals but said it would oppose any future effort to move away from a fixed $1.00 net asset value.

The extensive money market fund rule changes originally were proposed in June largely in response to a run on the Reserve Primary Fund, which “broke the buck,” or fell below a $1.00 net asset value, or NAV, in 2008, when Lehman Brothers bonds it owned defaulted following that firm’s collapse and fund investors rushed to sell their shares.

The rule changes address fund liquidity and disclosure requirements as well as their reliance on rating agencies. Notably, they include a requirement that funds enhance their disclosures by reporting on a delayed basis a “shadow” NAV, meaning the fund’s actual net “mark to market” NAV, rather than the stable $1.00 NAV at which fund shares are bought and sold.

“I believe this new disclosure will impose a discipline on fund managers to avoid taking undue risks that may result in the disclosure of a lower than expected shadow NAV,” SEC chairman Mary ­Schapiro said in opening remarks.

Even as the commission prepared to vote on the measures, Schapiro stressed that the SEC staff are considering additional reforms, some of which are controversial.

They include a floating, rather than a stable, $1.00 NAV, which the industry opposes; a private facility to provide liquidity to funds in times of stress; and a two-tiered system of money market funds, with a fixed NAV only for funds subject to “greater risk-limiting conditions” and possible liquidity facility requirements.

In addition, she said the additional changes could include options under discussion by President Obama’s working group on financial markets, which is being headed by Treasury Department officials.

The group is several weeks behind a self-imposed deadline for filing a report.

The rule changes drew some positive reactions, with the ICI worried about the SEC’s future proposals.

Paul Schott Stevens, ICI president and chief executive officer, said the group supports the measures the SEC approved yesterday, but will continue to “strongly” oppose any move to directly or indirectly require funds to abandon a fixed $1.00 NAV “that has been a defining feature of these funds.”

“Investors and issuers in the money market have filed extensive comments with the commission, and they have been almost unanimous in pointing out the serious damage that floating these funds’ NAV could inflict on investors, markets, and the economy,” Stevens said in a statement.

Mike Sebesta, director of liquidity management for StableRiver Capital Management, applauded the rule changes.

“I think it’s very positive for the industry,” he said. “It puts the industry at a safer spot improving credit quality, improving liquidity, and those are all very constructive for the industry.” He added that he believed most of the industry has already moved “very close” to these changes.

Kevin Bannerton, managing director at DWS Investments, said his firm is supportive of the new regulations, and is trying to implement at least some of the further improvements that Schapiro said the SEC would consider in the future — including real-time disclosure of funds’ shadow NAV.

Bannerton said DWS has already registered, but not yet launched, what may be the first variable NAV money market fund, designed to give institutional investors greater transparency and choice.

“We feel that a variable NAV would take this concept [shadow NAV] a step further and provide investors with daily transparency,” he said.

While the rule changes are intended to raise funds’ liquidity, they would also likely result in reducing what are already paltry yields, market participants said yesterday.