Despite the expectation that a prominent Boston real estate developer would be launching his campaign for mayor this week, he announced Monday that he would not be running.

Tom O’Brien, CEO of HYM Investments and former city planning chief under then-Mayor Tom Menino, released a statement Monday afternoon saying he had given “thoughtful consideration” to joining the race but ultimately opted against it.

“I care deeply about this city and have always looked for meaningful ways to serve,” O’Brien said. “The value of service — to others and to community — is something my parents instilled in me, a core part of my faith and a guiding force in both my professional life and personal life.”