Alector, Inc.

Our corporate headquarters are currently located in South San Francisco, California, where we lease approximately 105,000 square feet of office and laboratory space. The term of the lease agreement expires in May 2029, with an option to extend the term of the lease for an additional 10 years. The lease agreement also provides us a right of first offer to expand into available office space in the building. We subleased approximately 9,300 square feet of our corporate headquarters in February 2023 with a lease term that expired in July 2025. We also subleased approximately 13,000 square feet of the corporate headquarters in February 2025 and expanded the sublease to 15,200 square feet in August 2025, with a lease term that will expire in March 2029. We also subleased approximately 7,700 square feet of the corporate headquarters in December 2025, with a lease term that will expire in July 2027. We lease approximately 18,700 square feet of additional office and laboratory space in Newark, California. In August 2024, we approved a plan to transition operations from our laboratory and office space in Newark, California to our South San Francisco headquarters. Our intention is to sublease the Newark facility. If required, we believe that suitable additional or alternative space would be available in the future on commercially reasonable terms.