Cambridge-based developer Urban Spaces has obtained permanent financing for a speculative office building that’s scheduled to accommodate online marketplace CarGurus’ expansion.

People’s United Bank furnished a $44 million fixed-rate, long-term loan for the 60,000-square-foot building at 121 First St. scheduled for completion in January. Goedecke & Co. Principal Mike Surprenant sourced the financing.

CarGurus agreed to become anchor tenant of the project last year after raising $150 million in a 2017 initial public offering. The new offices supplement CarGurus’ existing Cambridge offices at 2 Canal Park and 55 Cambridge Parkway.

Designed by Perkins Eastman and built by Nauset Construction, 121 First St. contains 53,000 square feet of office space, 7,000 square feet of retail and 50 parking spaces.

Urban Spaces specializes in mid-sized, transit-oriented projects and also plans to relocate its headquarters to the property early next year from 111 First St.

“121 First’s prime location in Cambridge’s First Street Corridor, coupled with a long-term lease from CarGurus, enabled us to secure favorable terms and position the building for long-term success,” Paul Ognibene, CEO of Urban Spaces, said in a statement.

The office development is part of a $250 million project by Urban Spaces along the First Street corridor. The firm has approvals for 250 apartments, 53,000 square feet of additional office space and 50,000 square feet of retail.