David Greaney weaves through the narrow streets of Boston’s Financial District on a chilly September afternoon, pointing out buildings he has owned, still owns, or has considered buying. Nearly every block has his mark.
Dressed in green slacks, a starched white button-down shirt and a black blazer, the 6-foot-4 Irishman ducks into One Liberty Square, a 13-story office building he bought two years ago for $45 million. He redid the common areas, and occupancy at the Class B building climbed from 78 to 99 percent.
“I’m pretty sure we wouldn’t be at 99 if we didn’t clean up the lobby, if we didn’t build this space here, we didn’t upgrade the gym,” Greaney said, as he showed off the tenants lounge, which has a cold brew coffee bar, pool table and flatscreen TVs.
The 1920s tower isn’t flashy. There’s no gleaming glass curtain wall, no marquee anchor tenant. But that’s the point. Over the past two decades, Greaney has built his more than $2 billion investment firm, Synergy, on exactly this kind of property — older, mid-market buildings that form the backbone of Boston’s commercial core and which Greaney perceives could be better than they are.
Greaney, 50, went on a buying spree after the Great Recession, snapping up these types of buildings, upgrading them and often unloading them for a tidy profit. Greaney says his “spidey sense” told him to take a break from investing in the late 2010s because the market had reached an inflection point.
Once again leaning into his instincts, Greaney is back in buy mode. Synergy has spent $489 million to buy five distressed buildings since 2023, growing its Boston portfolio to 6.6 million square feet. The firm bought One Liberty for 17 percent less than the previous owner paid a decade ago. It paid $76.5 million for the debt on 179 Lincoln Street, an office building Blackstone bought for $156 million in 2020. And in April, it bought its largest building yet, a 32-story tower at 99 High Street for $227 million, 17 percent less than the building traded for in 2005.
Boston has been slower to bounce back than other cities like New York. Remote work and corporate downsizing pushed the overall vacancy rate to about 21 percent, up from 12 percent in the first quarter of 2020, according to JLL. But even Class A towers are offering concessions, and mid-market landlords face the added challenge of aging infrastructure.
Industry insiders who watched Greaney profit in the last downturn are taking notice. He earned respect for spotting the last cycle, and a few other buyers have started to follow his lead.
“Other than Greaney, I don’t think there’s a really good list of investors out there who have broken through and are buying these things,” said Newmark broker David Martel. “Greaney’s been the guy. In my mind, he’s the only guy.”
Luck of the Irish
The gregarious, no-nonsense Greaney has forged a reputation as both a risk-taker and a pragmatist, the rare operator who can go toe-to-toe with institutions while moving with the agility of a private investor.
Commercial real estate is a long way from where he started. In 1995, Greaney landed at John F. Kennedy International Airport, a 19-year-old from the working-class city of Limerick, Ireland, with a degree from University College in Dublin and a summer work visa. He got a job as a busboy in Ocean City, Maryland. After the season ended, he spent a month visiting Washington, D.C., Philadelphia, New York and Boston.
“I really just fell in love with Boston when I got here,” Greaney said in a conference room at Synergy’s downtown office. “I felt like the Irishness of the city is certainly beneficial, but really just the geography. It’s a good-sized city, there’s things to do, it’s very manageable, very walkable.”
He deferred an offer from KPMG in Dublin and moved to the United States with no job prospects. Within a couple weeks, he landed a gig through a temp agency at Harvard Management Company, the entity that manages the university’s endowment. That soon turned into a full-time position.
“I got a little lucky, I guess. Not many immigrants come to the city of Boston and get a job at Harvard,” Greaney said.
Betting it all
Greaney left Harvard for a job at PricewaterhouseCoopers, where he soon found himself on the partner track.
“I was doing fine, but I really just still had this kind of desire to start my own business,” Greaney said. He took a break and traveled to Australia, Asia and Europe. At that time, a friend introduced him to a fellow Irishman, John McGrail, who owned a modest Boston real estate operation, Mayo Group.
“I loved his story. He came with not much and built a small real estate business — at that time maybe 200 or 300 apartments,” Greaney said. “But he was looking to grow his business and needed a little bit more help on the finance and structuring side.”
In 2001, Greaney joined the Mayo Group, calling on his finance background to help secure equity and debt for deals. At the same time, he started to buy a few of his own run-down residential buildings, renovate them and sell them for a profit.
“If I proceeded with that project … I’d be back tending bar in Ireland or something.”
Two years later, Greaney founded Synergy, a name meant to reflect all the moving parts that have to align in any real estate deal. He took his life savings of $250,000, and, with a $900,000 loan from another developer, bought a 32-unit residential building in Chelsea, Massachusetts.
It was the days of easy credit and fast-moving condo sales before the Great Recession.
“There was no income verification or asset verification. People were buying condos with their signature,” Greaney said. He renovated, then sold all the units in a year. “We made a couple of million bucks,” he said.
That first deal set the tone for Greaney’s approach. He leaned into the momentum, trusted his instincts and took risks.
“At the time, I’m 27, 28. I first had to do a deal and I didn’t have anything to lose,” Greaney said. “I wasn’t married, didn’t have any kids. It was like I didn’t know any better, I guess. I was just like, let’s go.”
A gut feeling
By 2006, the firm had churned through roughly 120 condos in Boston and its suburbs, all financed with no outside capital. But as the market heated to a boil, he sensed the party was nearing its end — just as he closed on a downtown office building he intended to flip into residential units.
“It was gonna be a good size, 60 downtown units. I got approved. I’m supposed to start construction in 2007,” Greaney said. He listened to the gut feeling and changed his plans, inking a 10-year, 60,000-square-foot lease on the entire building.
The real estate market got hit by the Great Recession, credit dried up and property values tumbled. Boston’s condo market, like much of the country’s, slumped. Prices fell sharply, sales slowed to a crawl, and many projects were delayed, converted to rentals, or sold off in bulk to investors at steep discounts.
“Clearly, I look at that as a pivotal moment,” Greaney said. “If I proceeded with that project … I’d be back tending bar in Ireland or something.”
As he pivoted away from residential, Greaney started to zero in on downtown Boston’s overlooked office buildings. He saw opportunity in the class B buildings that make up almost half of the city’s office stock. As his projects grew bigger, he tapped into Ireland’s Celtic Tiger economic boom, raising $100 million from personal connections and acquiring 11 Class B office buildings.
“Dublin’s tiny, so it was very easy to connect to the moneyed class, and it was so much money that was available to everybody,” Greaney said. “It was easier to raise money at that time in Ireland than it has ever been and ever will be. So I was just kind of in the right place at the right time.”
A $5 million gamble
During the financial crisis, Greaney focused on keeping his buildings full with a mix of mid-sized tenants from industries like law, finance and technology. By 2009, he was ready to jump back into the market. With a $2.5 million loan from a credit union, he inked a $5 million deal for a 50,000-square-foot vacant office building, the first to trade in the city post-crisis.
“I kind of gulped when I found out I had the deal,” Greaney says. “I thought, ‘am I crazy?’”
The bet paid off. He leased out the building in less than a year and recapitalized it for $18 million. Buoyed by that success, he set his sights on expanding Synergy’s portfolio. Greaney grew his portfolio from 1 million to 4 million square feet.
“Once his bets started to pay off, a lot of people wanted to be around him,” Martel, the Newmark broker, said. “Not only did they want to be around him, they wanted to invest with him, they wanted to emulate him.”
Martel estimates that half of the city’s Class B building sales in the last 10 years were influenced by Greaney.
“He had that much of an impact,” he said.
There was a moment, Greaney said, when the worry that shadowed him finally lifted. About 2017, when he was in his early 40s, he had shed all his no-recourse debt and had a “significant amount” of cash in the bank.
“I was finally able to take a breath and go, ‘I’m never gonna be poor again,’” Greaney said. “It was just good to be there.”
Post-Covid conviction
During the pandemic, Greaney approached office investing the same way he had weathered the last downturn. In the early months, he dove deep into tenant relations, scrutinized leases and met with tenants. The work was painstaking — hundreds of face-to-face meetings, real-time tracking of rent payments — but it paid off. Between April 2020 and April 2023, Synergy collected 97 percent of contracted rents, even as occupancy dipped from 95 percent to the high 80s.
In 2023, as Boston slowly returned to the office and companies signaled a desire to bring employees back, Greaney started to underwrite new office deals. In September, Synergy made its first post-pandemic purchase at One Liberty Square. The historic, barrel-fronted building is home to several law firms, a biopharmaceutical company and AIG; it commands rents in the high $50s per square foot.
More deals followed. In April, Synergy closed its biggest deal ever — the $277 million acquisition of the Class A tower at 99 High Street. Tenants such as the HR consulting firm Mercer, biotech company enGene and HSBC pay rents in the $70s per square foot.
“He moves with conviction, and if you look at what he’s done in the last few years when the entire market by and large was running away from office, Dave saw what he felt was a generational opportunity to invest at low values,” Mark Van Zandt, co-head of real estate at King Street Capital Management, said. King Street financed the deal.
Recovery mode
The Boston office market is still under pressure. But there are signs the market is turning a corner. Leasing was up almost 14 percent year-over-year in the second quarter of 2025, according to Newmark. The vacancy rate has decreased for the fourth consecutive quarter, per JLL.
Greaney is candid about the headwinds but still confident in the fundamentals: “The institutions, the universities, the talent — that’s not going away,” he said.
As in the last market slump, Greaney has stuck to his thesis: Seek buildings with hidden potential, upgrade them with amenities and double down on leasing. Sell or recapitalize in three to five years.
“I think that Dave is doing a very good job of focusing on buildings that can be improved to meet the tenant demand that are in locations where tenants already want to be,” JLL broker Bryan Sparkes said. “He’s buying buildings that have really good potential that might not have been uncovered.”
While he waits to see whether his knack for sniffing out potential will pay off, Greaney can be found at one of the 12 restaurants he owns and operates.
At one, Bostonia Public House, the annual St. Patrick’s Day celebration has grown in step with his profile (and his family — Greaney now has seven children).
“It used to be a fairly low-key affair,” Van Zandt said. Had Greaney foreseen the growth of the saint’s day, too? “Now,” Van Zandt added, “it’s like a holiday in Boston.”