Prop B is a charter amendment on San Francisco's Nov. 3 ballot. It would let the city set up its own lender and, later, a public bank. It needs a simple majority to pass.

How it would work

First, the city could create a nonprofit municipal finance corporation once it has enough money to do so, according to the League of Women Voters of San Francisco. This lender could make loans and investments but could not take deposits. SPUR said most of its loans would go through community lenders, known as CDFIs.

After three to five years of profitable operation and approval from regulators, the lender could become a public bank. SPUR said that bank could hold government deposits such as tax money, but not personal accounts, and would not run ATMs. Both would be barred from investing in fossil fuels, weapons makers, prisons and businesses with labor violations.

KQED said San Francisco would be the first U.S. city with a municipal bank if the plan is carried out.

Cost

KQED cited the city controller's estimate that costs could range from $310 million to $460 million over eight years. KQED also noted the bank does not yet have dedicated funding.

Who is for and against

The League listed supporters including the SF Public Bank Coalition, the SF Labor Council, the Affordable Housing Alliance and the SF Tenants Union. They say a public bank would offer lower-cost loans for housing, climate projects and small businesses. Opponents in the official arguments say startup costs are too high while the city faces big deficits.

SPUR supports the idea of a public bank but opposes Prop B. It said the detailed rules don't belong in the city charter and could be set by ordinance instead.

More on the San Francisco ballot: where and how to vote in SF, when SF results come out and Props D, E and F compared.

How to vote

Election Day is Tuesday, Nov. 3. Polls and vote centers close at 8 p.m., and mailed ballots must be postmarked by Election Day and arrive within seven days. You can check your registration and ballot status at sos.ca.gov/elections. California lets you register and vote the same day at a vote center.