It’s hard to say who gets more out of Mitt Romney’s increasingly cozy relationship with Washington, D.C., lobbyists — the presumptive GOP nominee or the K Street insiders rounding up checks for him.

Romney’s success in outraising President Barack Obama last month was thanks in part to his exclusive team of Beltway lobbyist bundlers, who have collectively pulled in $1.2 million for his campaign, according to the Center for Responsive Politics.

But Romney’s friends on K Street, who include not only fundraisers but an inner circle of well-placed strategic and policy advisers, are reaping their own rewards. The top bundlers, many of whom Romney has not identified, enjoy weekly telephone briefings with the campaign, VIP entry to exclusive receptions and retreats and, in some cases, the chance to bend Romney’s ear on policy issues.

Romney’s K Street love-fest started slowly. Attacks on Washington insiders have long been a campaign staple for Romney, who assailed Sen. John McCain (R-Ariz.) for his ties to lobbyists during the  2008 primaries and who leveled similar attacks on former Speaker Newt Gingrich (Ga.) during this campaign. Never a Washington fixture, Romney was slow to win over some of the bundlers who had raised large sums for McCain and President George W. Bush.

But in recent months, Beltway lobbyists have embraced Romney eagerly, and the campaign has wooed bundlers more aggressively, dangling rewards to “Stars,” who round up $250,000 worth of donations, and “Stripes,” who collect $500,000.

Romney’s Washington outreach has gone so well that his campaign scheduled three fundraisers this month for the D.C. area — not traditionally among the country’s top regions for political donations.

Many Washington-area lobbyists helping Romney say they expect no reward. The campaign’s weekly conference call with top bundlers and donors is held at 12:30 p.m. on Fridays — a time when many lobbyists say they’re out to lunch.

For some, a June 22-24 retreat that will allow top donors and bundlers to hobnob with Romney and his top aides in Park City, Utah, holds little appeal. Said one lobbyist bundler: “I am going to the beach.”

Still, the Washington lobbyists who are tapping their friends, relations, business associates and clients for checks of as much as $75,800 — the legal maximum that an individual may give to Romney’s joint fundraising effort with the Republican National Committee — say the Romney campaign is characteristically businesslike about rewarding donors.

“The Romney folks, to their credit, are very metric-oriented,” said one lobbyist bundler who, like many on K Street raising money for Romney, asked not to be named. “So if you commit to do something, the expectation is you are going to achieve that objective. And if you don’t, you are not going to get the things that were going to go with that.”

Romney’s K Street backers represent dozens of major companies in the banking, energy, health care, insurance and real estate industries. His top bundlers include lobbyists representing Altria, Goldman Sachs, Kraft Foods Global and Microsoft, among others.

Also bundling for Romney are top lobbyists at such firms as Ogilvy Government Relations, Dutko Grayling and DLA Piper, whose clients include big companies such as Chevron Corp., Google Inc., Pfizer Inc. and U.S. Airways.

Romney’s Washington fundraising events have given special entry to “Industry Finance Chairs,” who on some occasions have enjoyed a special reception with Romney, plus a stop-by from the candidate at policy roundtables on issues such as energy, education, health care and foreign policy.

Romney’s top lobbyist bundler, for example — Patrick Durkin, managing director at Barclay’s Capital in New York, who has collected almost $1 million for the candidate — was “Financial Institutions & Markets” finance chairman at a Romney fundraiser at the JW Mariott in February.

Other influential Beltway lobbyists playing a lead role in Romney’s Washington operation include Drew Maloney, CEO of Ogilvy Government Relations, Wayne Berman, Ogilvy’s chairman, and Goldman Sachs lobbyist Joseph Wall, who has led efforts to raise money from Washington-area young professionals, including at a rooftop Homer Building reception scheduled for June 25.

Other top Washington advisers don’t show up in public disclosures. Candidates are required by law to publicly disclose their lobbyist bundlers.

But Romney has failed to release the names of his non-lobbyist bundlers, as has Obama, and as did McCain in 2008, prompting criticism from watchdog groups. Some members of Romney’s Washington team are neither lobbyists nor bundlers, allowing them to fly below the radar.

One of Romney’s top lobbyist advisers doesn’t show up in public records at all: Jack Gerard, president and CEO of the American Petroleum Institute, who is said to weigh in with the candidate on energy issues.

Gerard is among Romney’s most trusted advisers and is “a very serious player across all dimensions,” including finance, policy and strategy, one Romney bundler said.

“If there’s a single ‘go-to’ person in Washington for the Romney campaign, it is Jack Gerard,” the lobbyist said. “He’s Hertz, and there’s no Avis.”

Also close to Romney are Bill Kilberg, a partner with Gibson, Dunn & Crutcher, who co-chairs Romney’s national finance committee and who gives him policy advice on labor issues; and his wife, Bobbie Kilberg, president and CEO of the Northern Virginia Technology Council, who is one of Romney’s lead fundraisers in the area. Neither is a lobbyist, so they don’t turn up on public disclosures.

Romney “is very popular in Washington,” Bill Kilberg said. “It’s not been difficult to raise money for him in Washington.”