As out-of-town investors pay top dollar for office towers in Greater Boston, the region’s advantages in the new economic order could justify the prices, real estate executives said at a forum Wednesday.

Boston’s tech and life science clusters, universities and teaching hospitals will continue to drive tenant demand and support rent increases in coming years, Beacon Capital Partners CEO Alan Leventhal said.

"This city is getting more developed, it’s getting larger in population, it’s growing again, and I think it’s going to look dramatically different in 10 or 20 years," Leventhal said.

In one of the largest pending transactions, Oxford Properties Group of Toronto has reportedly agreed to buy five Boston and Cambridge office towers from New York-based private equity firm Blackstone Group for $2.1 billion. The portfolio includes 100 High St., 125 Summer St., 60 State St. and 225 Franklin St. in Boston and One Memorial Drive in Cambridge.

Tenant demand will continue to spike along mass transit lines, and the Red Line continues to be the top choice among tech companies, Leventhal said. The traditional tech cluster in Kendall Square has been augmented by a growing number of startups in Downtown Boston and the Seaport District.

Representing the tenants’ perspective, David Richardson, a partner at McCall & Almy, questioned whether the latest wave of investors has unrealistic expectations of returns.

"Just because somebody buys a building for $600 a foot doesn’t mean that the net rent has to be $40 a foot," Richardson said. "I would argue these investors should be comfortable with a 2 or 3 percent return."

The forum was sponsored by the Commercial Brokers Association, a division of the Greater Boston Real Estate Board.