An independent expenditure political action committee backed by the Massachusetts real estate industry dumped hundreds of thousands of dollars into local races this year and so far tops the list of so-called super PACs that have poured cash into closely-watched Beacon Hill elections.

Reports filed with the Office of Campaign and Political Finance show the extent to which super PACs — which have no limits on the amount they can raise and spend so long as they do not coordinate directly with candidates — have waded into local contests.

For some of the candidates that drew the outside support, the dollars came at a crucial moment when they were either facing tough primary challengers, contemplating weighty topics on Beacon Hill, or staring down a difficult general election in November.

The Massachusetts Realtor Independent Expenditure Political Action Committee has so far spent the most money this year among super PACs, according to a compilation of reports put together by state campaign finance regulators only a week before the November election.

The super PAC has spent more than $216,000 on direct mailers, digital advertisements, and “list” purchases in support of both Democrats and Republicans, including more than $34,000 on Rep. Matt Muratore, a Plymouth Republican running against Falmouth Democrat Rep. Dylan Fernandes for a South Shore and Cape Cod Senate seat.

The spending group is backed by the Massachusetts Association of Realtors and the National Association of Realtors, which have fought against attempts in the Legislature to pass a fee on high-value home sales that supporters said would bring in much-needed cash for affordable housing, according to state data.

Muratore said super PAC spending decisions are not up to him because he is barred by state law from coordinating with the independent expenditure groups.

“I can only deal with what our message is, the message we’re trying to get out, and if it resonates with people,” he said in an interview. “The message is about the cost of the migrant crisis and about affordability issues and fiscal responsibility and transparency on Beacon Hill.”

Massachusetts Association of Realtors CEO Theresa Hatton said spending decisions are made by the super PAC’s board of directors.

“The board is comprised of Realtors from across the state who review issues such as candidate policy positions on housing-related issues when making decisions on which candidates to support,” Hatton said in a statement.

Fernandes is also no stranger to dollars from super PACs, having drawn backing from ones run by the Massachusetts Teachers Association and the Environmental League of Massachusetts. He applauded the two organizations in a statement to the Herald.

“As someone with a strong track record of supporting public education and helping children succeed, along with being a champion for protecting and preserving our environment, it’s an honor to have the support of the Mass. Teachers and the state’s preeminent environmental organization,” Fernandes said.

The super PAC backed by the Massachusetts Association of Realtors has also spent more than $31,000 in support of Joseph Pacheco, a Raynham Democrat running for a southeastern Massachusetts Senate Seat against Taunton City Councilor Kelly Dooner, a Republican.

It is not the only super PAC to back Pacheco — the Massachusetts Teachers Association Independent Expenditure Political Action Committee also shelled out thousands to promote his campaign.

In a phone call with the Herald, Pacheco said he does not control who super PACs support but he is “grateful for organizations, associations who represent the working class people of Massachusetts.”

He said some of the super PACs who support him represent “teachers, for example, and I would stand with teachers each and every day, compared to the ultra-wealthy who are donating to my opponent.”

“I mean honestly, no disrespect to you, but I’m not surprised that the Herald, again, is trying to give an advantage to the Republicans in these races because this is now the third story that looks like it’s going to go in Kelly’s favor,” Pacheco said when asked about super PAC spending in the race. “Kelly got a whole article about Charlie Baker endorsing her and I’ve been endorsed by every statewide public safety organization and there’s been no story on that.”

The Massachusetts Teachers Association, whose super PAC spent more than $183,000 on local races this year, according to state data, said a “member-led” committee evaluates and recommends “pro-education” candidates to support.

“MTA members proudly campaign for the candidates fighting alongside educators for the public schools and colleges our commonwealth deserves. And that commitment to candidates extends to financial support that our members know is crucial in competitive races,” a spokesperson for the union said in a statement.

The Commonwealth for All Independent Expenditure Political Action Committee — another super PAC that has received money from various unions in the past but has only drawn cash this year from the National Association of Government Employees — also spent $11,265 on direct mailers in opposition to Dooner, according to state records.

Dooner said she is proud that no “special interest groups that advocate for higher taxes are promoting my candidacy.”

“These mailers and all this special interest money for my opponent proves that I am the only candidate who can be trusted to hold the line against taxes, protect people’s wallets, paychecks, and savings, and fight the Healey administration’s costly influx of migrants,” she said in a statement to the Herald.

A spokesperson for the National Association of Government Employees and an employee of the union listed on state campaign finance filings did not respond to a Herald inquiry.

Regular political action committees, which can only take in contributions from individuals but are afforded no-limit spending opportunities so long as they file the proper paperwork, have also spent hundreds of thousands of dollars this year on local candidates.

A PAC backed by 1199 SEIU, a union representing healthcare workers in Massachusetts, has so far spent more than $272,000 in support of more than 20 candidates for House and Senate seats, including Pacheco and Fernandes, according to state data.

The political action committee led by Massachusetts House Republicans spent nearly $37,000 in support of conservative candidates, the state data shows.