The request is part of a nationwide campaign to get investors to divest from private prison companies. Most recently, the campaign has focused on local institutions such as cities, counties and universities.
"It's harder to put pressure on big banks, but we can exert more pressure on cities to push these financial institutions so that our money isn't going into the private prison industry," said Jamie Trinkle, divestment campaign coordinator for Enlace, a Portland-based nonprofit.
Immigrants held by immigration officials in Portland are transferred to GEO Group's Northwest Detention Center in Tacoma, Wash.
Portland holds $40 million in Wells Fargo bonds.
Wells Fargo does not own any shares of the GEO Group or Corrections Corporation of America, the nation's two largest private prison companies. The company administers a mutual fund that holds less than 1 percent of outstanding shares of GEO Group. Corrections Corporation of America is Wells Fargo's banking client.
"We respect the perspective of these activist groups as it specifically relates to these two companies. (But) we have no role in advocating a public policy viewpoint on immigration or the use of private prisons ... that should be addressed to the appropriate elected officials," Wells Fargo spokesman Tom Unger said in a written statement.
The company's managers should make portfolio management decisions based on the best investments for clients, Unger said.
Activists submitted a draft resolution to several city commissioners, asking that Portland officially cut its ties with Wells Fargo and other financial institutions.
City officials did not comment Wednesday on the divestment campaign, but Portland is working on broad criteria for ethical and socially responsible investment policies, spokeswoman Abby Coppock said.
Those include avoiding companies whose practices damage the environment, who engage in abusive labor practices or violate basic ethical standards, among others.
The private prison industry has seen huge growth in recent years when it comes to immigration detention. About half of the 400,000 immigrants held annually are now housed in private facilities.