With the tallying of votes complete, an accounting of super PAC spending is in order. The outside groups, also known as super political action committees (PACs), raised $5.6 million, almost $2 million more than the $3.8 million spent in the 2013 race, the last open contest for mayor.

In 2013, much of the super PAC spending came from unions looking to support Marty Walsh, then a Dorchester state representative and labor leader, in his successful quest for the mayor’s chair.

But union support was split among the 2021 candidates, and one of the biggest spenders was Jim Davis, the New Balance chairman and a top Republican donor.

A back-of-the-envelope tally indicates Davis, who dumped $600,000 over two days into the contest between City Councillors Michelle Wu and Annissa Essaibi George, spent roughly $12 per vote. Essaibi George, who was supported by the Davis-backed super PAC “Real Progress Boston,” received 50,879 votes to Wu’s 91,239, a winning margin of 28 percent for the winner.

“Real Progress Boston,” and the similarly named “Bostonians for Real Progress,” also received funding from police and firefighter unions as they took to TV and radio in an effort to support Essaibi George and knock down Wu.

Essaibi George had asked her super PACs to stay out, a request they ignored along with Wu’s ask that they stay positive. Under campaign finance rules, super PACs are not allowed to coordinate with candidates.

Wu had super PACs of her own – mostly funded through environmental advocacy groups and attorneys. They stayed positive throughout the campaign, and together, they spent $1.9 million in their efforts to bolster her candidacy. One super PAC, “Boston Turnout Project,” was run by Jason Burrell, who, like Wu, is a former aide to US Sen. Elizabeth Warren. The group focused on TV ads and digital advertising.

The other super PAC, the Environmental League of Massachusetts Action Fund, took in money from the Environmental League and the League of Conservation Voters, as well as the Green Advocacy Project, a Palo Alto-based outfit with veterans of Bernie Sanders’s 2016 run for president on its board.

That group focused on turning out environmentally minded voters who showed up for the 2020 Democratic Senate primary between incumbent Ed Markey, who supported a package of environment-friendly proposals called the “Green New Deal,” and then-US Rep. Joe Kennedy III.

The super PAC promoted Wu on social networking apps like Snapchat, along with mailers, according to Casey Bowers, the outside group’s treasurer.

In a wrap-up summary of its efforts provided to the Reporter, the super PAC said it was “informed by the strategic landscape facing the candidates; available public polling; and the overarching goal of elevating and highlighting the importance of climate and environmental policy.” The group sought to “consolidate liberal and progressive support” behind Wu’s candidacy.

The super PAC also focused on engaging Hispanic voters. “Noting that public polling showed Hispanic voters remained split between (Acting Mayor) Kim Janey and Michelle Wu during the preliminary election, ads were translated into Spanish and targeting was segmented to ensure native Spanish-speakers would receive Spanish-language ads, improving our ability to break through and engage these voters,” the summary said.

Their mailers went out to 15,000 households in three waves during the preliminary election, and helped turn out their “universe” of voters. In the general election, the super PAC spent $75,000 and focused on digital ads. Their summary says 90,000 Boston voters were reached.

With the mayoral election in the rearview mirror, the super PAC is now turning to statewide races and State House contests on the election calendar for September 2022. House and Senate lawmakers, as well as the offices of governor, lieutenant governor, treasurer, auditor, and secretary of state will be on the ballot.