Boston-based Gibson Sotheby’s International Realty announced it’s bought the Madden Group, a Portsmouth-based, two-agent brokerage.

The move marks the large brokerage’s first physical presence in the New Hampshire market, although its purchase of a 16-agent brokerage just across the state line in Newburyport, Massachusetts in 2023 gained it agents that served the state.

Financial terms of the deal were not disclosed.

“Jenn [Madden] has built a brokerage that reflects many of the values we’ve prioritized as we’ve grown: a boutique culture, close collaboration, and a deep commitment to the communities it serves,” Gibson Sotheby’s chairman and founder Larry Rideout said in a statement. “This builds on a business already active in New Hampshire, where our agents have long served clients from Newburyport and across coastal New England, and Jenn’s team is an exceptional cultural fit.”

Madden Group broker/owner Jennifer Madden will join Gibson Sotheby’s as its vice president for New Hampshire, and her brokerage’s short-term vacation rental management division, Rising Tide Rentals, will continue to operate under its existing brand.

“Since 2010, we’ve built our business on trust, local expertise, and strong relationships across the Seacoast region,” Madden said in a statement. “Joining Gibson Sotheby’s International Realty allows us to pair that foundation with the support and global reach of the Sotheby’s International Realty brand, elevating what we can offer our clients while continuing to serve the communities we know best.”

Gibson Sotheby’s reported $3.88 billion in sales volume in 2025, which the brokerage said put it ahead of all others in Massachusetts.