Bob Knakal, James Nelson and HFF Boston executive director John Fowler were Paul Massey’s top fundraisers as he outpaced incumbent Mayor Bill de Blasio on his way to a $1.6 million campaign haul over the past six months.

In the months ahead, the two candidates’ fundraising efforts will play a key role in shaping the race for City Hall in November.

Massey, who received the endorsement of the Independence Party of New York earlier this month, raised about $500,000 more than the $1.1 million de Blasio raised since July, according to disclosures published by the New York City Campaign Finance Board on Tuesday.

“This is a significant milestone, and we are just getting started,” the Cushman & Wakefield investment-sales president said in a statement.

In addition to funds raised from over 800 donors, Massey made several personal loans to the campaign totaling $1.3 million, bringing his total fundraising for the period to $2.9 million. While he’s clearly the best funded of de Blasio’s potential challengers, Republican or Democratic, the campaign has little cash on hand — Massey’s been spending almost as quickly as he can fill the till.

The campaign has spent $1.9 million so far – the lion’s share of it on campaign workers and high-powered consultants such as pollsters Arthur Finkelstein and Doug Schoen, former Joe Biden speechwriter Ryan Clancy and Ann Hersberger, a fundraiser with ties to Jeb Bush. The real estate executive’s campaign has a current balance of about $937,000.

De Blasio, on the other hand, has a balance of $2.2 million. His fundraising total for this election cycle stands at $3.3 million. The mayor collected donations from 3,261 individuals, more than any other mayoral candidate during one filing period in recent memory.

As a political outsider with little name recognition with voters, Massey has his work cut out for him if he wants to unseat the Democratic incumbent in November’s election.

De Blasio will most likely participate in the city’s matching-funds program, which matches small donations on a $6-to-$1 basis, but limits campaign spending. His roughly $1 million raised in the most recent fundraising cycle will also translate to about $1 million in matching funds, a spokesperson for de Blasio’s campaign told The Real Deal.

Massey has said he will forgo matching funds, which places more pressure on him to outraise his opponent and tap big-money donors.

And to help raise that campaign cash, Massey has enlisted many of his pals in the real estate industry.

Knakal, in addition to making the maximum personal contribution of $4,950, bundled more than $113,000 worth of funds from 30 other donors, 21 of which gave the maximum amount.

Other top bundlers include CBRE’s Stephen Siegel, Goldberg Weprin real estate attorney Andrew Albstein and developer Alex Adjmi. All told, 60 intermediaries bundled a total of more than $995,000 worth of donations, or about 61 percent of funds raised.

The names of individual donors also reads like a guest list for Thursday’s Real Estate Board of New York gala. A non-exhaustive list includes Aby Rosen and Michael Fuchs, Simon Shkury, Simon Ziff, Robert Futterman, Peter Riguardi, Ziel Feldman, David Falk, Kevin Maloney, Edward Minskoff, Peter Hauspurg, Darcy Stacom, Ofer Cohen, Jay Neveloff, Joe Moinian, Ben Shaoul and Mitchell Steir.

On Monday, de Blasio criticized Massey for taking maximum-level contributions from some of the real estate industry’s biggest players.

“It does not surprise me that a millionaire developer would be able to turn to lots of other people in real estate and business and get a lot of large contributions. That doesn’t surprise me one bit,” he said in an interview with NY1 anchor Errol Louis, according to Politico. “I don’t think the people of this city are looking for a developer to lead us forward.”

In the past, de Blasio’s been able to rely on his friends in the real estate industry to help fill his war chest. During previous filing periods Bill Rudin, Sol Arker and Steve Witkoff were some of his top bundlers, and his former PAC Campaign for One New York collected large donations from Two Trees Management’s Jed Walentas. During this most recent filing, however, the mayor listed no intermediaries.

De Blasio’s individual supporters from the industry include Lawrence Benenson, Meir Cohen, Neil Dolgin, Winston Fisher and Albert Laboz.

New York City Comptroller Scott Stringer, said to also be weighing a run for City Hall, raised $346,385 from 457 contributors.