The owners of 33 Arch St. in Boston’s Downtown Crossing have chosen TIAA-CREF’s offer of $368 million as the winning bid for the 600,000-square-foot building, according to industry sources.

The owners are AREA Property Partners of New York, and Montreal-based SITQ, a real estate investment unit of Canadian pension-fund manager Caisse de Depot et Placement du Quebec. The deal is expected to see a cap rate lower than 5 percent. Locally, TIAA-CREF also controls 99 High St.

"It’s impressive that the asset could achieve that kind of pricing, and it’s indicative of the strength of the core Boston office marketplace," remarked one industry executive about the deal who requested anonymity.

The building at 33 Arch St. is one of few downtown core properties to hit the market in years, and Banker & Tradesman first reported that the property was coming to market.

While investment sales professionals said the price is high in May, when the story was first reported, whoever buys it will also own the 800-car garage that comes with the building, which is 89.25 percent leased. For comparison’s sake, Boston Properties recently purchased the 1.75 million-square-foot John Hancock tower in the Back Bay for $930 million, or roughly $530 per square foot.