The vast majority of money supporting the initiative to expand background checks on guns comes from just 10 ZIP codes in the Seattle area, much of it from people with ties to the tech industry.

An analysis of contributions reported to the state Public Disclosure Commission shows more than $2.8 million in contributions for Initiative 594 – or about 84 cents of every dollar contributed – comes from downtown Seattle, areas around Lake Washington and Shoreline. So far, the ballot measure to extend background checks from licensed dealers to most private sales has raised about $3.2 million, about three times more than the campaign for a counterproposal.

The other initiative, Protect Our Gun Rights, or I-591, only would allow changes to Washington’s gun control laws if a uniform national standard is adopted. The big donors to I-591 are a trio of groups opposed to further gun control measures.

Topping the list of donors to the Washington Alliance for Gun Responsibility is Paul Allen, co-founder of Microsoft, who gave the campaign $500,000 this month. He’s joined by former Microsoft CEO and new Los Angeles Clippers owner Steve Ballmer, who has contributed $250,000, and his wife Connie Ballmer, who has given $325,000. Bill and Melinda Gates gave $25,000 each.

Venture capitalist Nick Hanauer has contributed $385,000 and other members of the Hanauer family have given another $110,000. Ann Wyckoff, a long-time Seattle area philanthropist and heir to the PACCAR fortune whose occupation is listed as “volunteer” on the PDC reports, contributed $226,000.

The group has about 4,800 individual contributors and has drawn some out-of-state support, including $30,000 from Mayors Against Illegal Guns, a national group that has former New York City Mayor Michael Bloomberg as one of its co-chairmen.

So far, much of the $2.2 million the campaign has spent has been used for gathering signatures to get the measure on the ballot, political consultants and staff salaries.

Protect Our Gun Rights has received slightly more than $500,000 from Washington Arms Collectors, which bills itself as the state’s largest firearms and gun safety organization and sponsors the state’s largest gun shows throughout the year. It also has received $280,000 in cash and another $141,000 of in-kind contributions from the Citizens Committee for the Right To Keep and Bear Arms, a Bellevue-based Second Amendment advocacy group. It received another $100,000 from the Gun Owners Action League, which lobbies the Legislature and Congress and endorses pro-gun candidates.

The group also has about 285 individual donors who gave between $10 and $1,600.