PORTLAND — A series of real estate transactions that have the potential to transform Portland’s waterfront closed this week.

The Portland Co.’s complex at 58 Fore St. was sold on Monday to a group of developers, according to Tony McDonald, the broker with CBRE/The Boulos Co. who closed the deal. McDonald represented the property’s former owner, Phineas Sprague.

He wouldn’t discuss the identity of the buyers or a purchase price, citing a desire on the part of Sprague and the buyers to craft a press release to be released Monday.

The property, which has been on the market since 2008, consists of several brick red buildings that sit on approximately 10 acres at the foot of Munjoy Hill on Portland’s eastern waterfront. The Portland tax assessor’s office values the property and its buildings at $1.9 million.

The complex houses many businesses, including Portland Yacht Services, which is owned by Sprague; New England Fiberglass; and the Maine Narrow Gauge Railroad and Museum. It’s also home to several popular events, including the Portland Flower Show and Maine Boatbuilders Show, and is rented out for weddings and other gatherings.

As far as McDonald knows, the developers “don’t have any specific immediate plans” for the property, which got its start as a locomotive foundry in 1846. However, the events will remain at the site, he said.

One of the reasons developers want to be careful in how they craft their message is that they don’t want people to think the property no longer will be available for events, McDonald said.

The complex of buildings is not on the National Register of Historic Places, “but they are historic in the literal sense of the word if not legal,” McDonald said. “I don’t think anyone is planning to tear them all down. They’re too valuable and too charming.”

After the sale of The Portland Co. complex, McDonald also represented Sprague in the purchase of 15 acres on the other side of Portland’s waterfront, just west of the Casco Bay Bridge and approximately across the street from where developer J.B. Brown & Sons hopes to construct three new office buildings.

“The big picture on this whole thing is we’re selling Phin’s property to provide funding to build a new state-of-the-art small shipyard,” McDonald said.

The shipyard will be built on the 15-acre lot Sprague purchased in two deals that also closed this week, he said. Sprague purchased one portion from Pan Am Railways in a deal that closed Wednesday, and the other portion from gas company Unitil, which closed Friday, McDonald said.

Christopher O’Neil, a Portland Community Chamber consultant, recently told the Bangor Daily News that Sprague’s sale of The Portland Co. complex and his new shipyard could spur as much as a billion dollars worth of waterfront development.

“That will unleash a wave of positive development like we haven’t seen since after the Great Fire of 1866,” O’Neil said.