| Market Square | |
|---|---|
&sq=Qlik&lang=&file=File:Twitter_Offices_in_San_Francisco.jpg) The building in May 2023 | |
 | |
| Former names | Western Furniture Exchange and Merchandise Mart San Francisco Mart |
| Alternative names | Twitter Building |
| General information | |
| Architectural style | Art Deco (Additional elements of Mayan Revival and International Style) |
| Address | 1355 Market Street |
| Town or city | San Francisco, California |
| Country | United States |
| Coordinates | 37°46′35″N 122°25′01″W / 37.77639°N 122.41694°W |
| Year(s) built | 1936–1937 |
| Opened | July 31, 1937 (Dedication ceremony) August 3, 1937 (Official opening) |
| Owner | |
| Landlord | Shorenstein Properties |
| Technical details | |
| Floor count | 11 |
| Floor area | 1,000,000 square feet (93,000 m2) |
| Design and construction | |
| Architecture firm | Capital Co. Architects |
Market Square (formerly the Western Furniture Exchange and Merchandise Mart, the San Francisco Mart, and, colloquially, the Twitter Building) is an Art Deco building in the Mid-Market neighborhood of San Francisco, California, United States. Located at 1355 Market Street, it was constructed in 1937 and originally served as a showroom for retailers and wholesalers in the furniture industry. In the early 21st century, the building underwent an extensive conversion into office and retail space, and is most well known as the former headquarters of Twitter, Inc. and its successor X Corp. until 2024.