Nevertheless, the Rainforest Action Network said Wells Fargo's policy doesn't go far enough. The group, also based in San Francisco, said it still plans Wednesday protests outside several Wells Fargo offices, including its headquarters.

Wells Fargo pledged by year end to adopt new due diligence procedures for mid-size and large business clients in environmentally sensitive industries.

It will also adopt the "Equator Principles," drafted by the World Bank's private sector arm, to govern project financing in environmentally sensitive regions.

Wells Fargo, the No. 2 US mortgage lender, also said it will try to help customers qualify for more energy-efficient mortgage products, and encourage the construction and development of "green" homes.

"It's part of being a good corporate citizen, and it's also good business," said Mary Wenzel, Wells Fargo's vice president of environmental affairs, in an interview. "We plan to integrate this across our businesses, and devote efforts to develop environmental products that touch all our customers."

Michael Brune, Rainforest's executive director, said in an interview: "We're happy they're acknowledging the environment is something to pay attention to, but this policy doesn't meet the emerging industry standard -- to phase out investing in operations that would degrade endangered forests, and to develop an intelligent response to climate change.

"Citigroup, JPMorgan Chase, and Bank of America have all set forth policies that are clearer and stronger than Wells Fargo's," Brune added.

Wells Fargo said it adopted its policy after a six-month review by an internal committee.

Wenzel joined Wells Fargo after two stints at the US Environmental Protection Agency, where she worked with companies and community groups to develop policies. She said she has had limited communications with Rainforest.