SAN FRANCISCO—Exercising an option, Square Inc. is expanding its office lease at 1455 Market Street to 327,432 sq. ft. by early 2014.

The company, which enables credit card payments through mobile devices, signed a lease in November 2012 encompassing 246,078 sq. ft. of initial occupancy at the one-million-sq.-ft. tower, with an 81,354 square foot expansion option. The building is in close proximity to both Twitter’s new corporate headquarters and to some of San Francisco’s largest government and cultural institutions.

Hudson Pacific Properties Inc. owns the 22-story building. The lease backfills 238,367 square feet of space currently occupied by the building’s largest tenant.