Cousins Properties is set to buy the sail-shaped downtown tower overlooking Lady Bird Lake at 601 West 2nd Street. The Atlanta-based REIT is under contract to purchase the 35-story bulding for $521.8 million, the company announced Tuesday.

Dallas-based Trammell Crow Company and MSD Capital, a private investment firm that manages the capital of Michael Dell and his family, developed the 804,000-square-foot tower, which delivered in 2022.

The tower's offices are "fully leased to a Fortune 20 company through 2038" — presumably Google, which in preleased the entire building in 2021 — according to Cousins, which did not identify the tenant. Investment bank Eastdil Secured served as the exclusive advisor on the transaction.

“We are thrilled to add this iconic office property, with a strong investment grade customer, to our Austin portfolio,”’ the company’s Colin Connolly said. Cousins owns 300 Colorado, Colorado Tower, San Jacinto Center, and One Eleven Congress downtown as well as office properties in the Domain in north central Austin.

The Austin office market’s vacancy rate increase was among the highest in the nation in November, according to a CRE report.

Cousins expects the transaction to close this month.