Our Team

Rebecca Foster

Rebecca (she/her) is the founding CEO of the San Francisco Housing Accelerator Fund, a public private partnership that provides powerful new tools to improve the delivery of affordable housing. Since 2017, the Fund has invested over $300 million in housing preservation and development projects throughout San Francisco, supporting over 1,500 permanently affordable homes for more than 2,600 residents vulnerable to displacement and homelessness. Previously, Rebecca served as Director of Social Impact Investment under the late Mayor of San Francisco Ed Lee, and before that was a Vice President in Public Sector & Infrastructure investment banking at Goldman Sachs, where she raised capital for local governments, universities, non-profits, and utilities around the country. She received her BA. from Brown University and her MBA from the Stanford Graduate School of Business. Rebecca was appointed to the Board of Directors of the California Housing Partnership Corporation by Governor Newsom, and also serves on the boards of the San Francisco Friends School and ARTA, a whitewater rafting organization. She lives in San Francisco with her husband and three boys.

Tamar Dorfman

Tamar (she/her) joined the Housing Accelerator Fund as Chief Financial Officer. Most recently, she served as CFO of the Public Health Institute, one of the largest and most comprehensive public health organizations in the nation, where she oversaw the finance & accounting, grants & contracts, and audit & compliance teams. Tamar brings more than two decades of experience at non-profit and public sector organizations that promote equitable and just communities through economic development, public health, and affordable housing. Her career has focused on developing strong financial strategies and efficient operations so that organizations can maximize impact while ensuring compliance with funder and regulatory requirements. Prior to PHI & HAF, Dorfman was the Chief Financial Officer for PolicyLink, and the Mayor’s Offices of Community Investment and Housing in San Francisco (a precursor to the current Mayor’s Office of Housing & Community Development). She also served as the Fiscal Manager for the Corporation for Supportive Housing and was a Principal Budget Analyst for the City of Chicago. She holds a Masters in Public Policy from the University of Chicago and a Bachelor’s degree from Stanford University. Tamar lives in Oakland, where she was raised.

Kate Hartley

Kate Hartley (she/her), Chief Lending Officer to the HAF, has worked throughout the Bay Area on housing financing and development for over three decades. She began her career with a market-rate developer converting vacant factories into new residential developments in San Francisco. She then focused on affordable development, building housing for seniors, families, and people with special needs. As a regional financial consultant, Kate specialized in layering low-income housing tax credits, tax-exempt bonds, state subsidies, and HUD funds to help her clients build new developments and preserve existing homes. Kate worked at the San Francisco Mayor’s Office of Housing and Community Development (MOHCD) from 2014-2019, serving first as deputy director and later director, where she oversaw the financing and completion of 10,000 new or preserved affordable units. In 2019, Kate joined the HAF as Chief Lending and Investment Officer, working with the team on preservation and production investments that advanced new, cost-effective development models.  In 2022, Kate left the HAF to serve as the inaugural director of the Bay Area Housing Finance Authority, the state’s first regional affordable housing financing agency, where she worked to deliver the “3 Ps” – affordable housing production and preservation and the protection of vulnerable residents – to the entire Bay Area. Kate is thrilled to return to the HAF and once again employ its unique focus on innovation and efficiency to deliver the affordable housing California needs.

Jan Lindenthal-Cox

Jan Lindenthal-Cox (she/her) has dedicated her career to addressing economic and social inequity by creating affordable housing opportunities for low income community members across the Bay Area. During her more than 30 years in the SF Bay Area, Jan has overseen the development of more than 5,000 affordable homes across dozens of properties many of which have won national and global awards of excellence. Prior to joining the HAF, Jan led the Development Team for MidPen Housing, one of the nation’s largest non-profit developers and owners of affordable housing with real estate assets totaling well over $1 Billion. In this role she managed a team of 50+ professionals and a pipeline of more than 5,000 units. Jan also served as the Executive Sponsor for MidPen’s Collective Voices for Equity Council, helping to shape and lead MidPen’s Equity Agenda.

Jan has received numerous industry recognitions including the Inspirational Non-Profit Leader Award from the Non Profit Housing Association and the Pioneer Award from the Affordable Housing Management Industry of Northern California, both awarded in 2022. In 2017 Jan was recognized by the San Francisco Business Times as a “Woman of Influence in Real Estate” and in 2013 as one of the “Most Influential Women in Bay Area Business”, Jan’s expertise in housing and community development is widely sought. She has served on the Boards of the California Coalition for Rural Housing (CCRH), Silicon Valley @ Home and Build It Green and has been an active supporter of and trainer/mentor for CCRH’s Internship Program for Diversity in Community Development and currently serves on the Advisory Committee for CCRH’s Emerging Leaders Fellowship Program.

Prior to MidPen, Jan held leadership posts at South County Housing, the Santa Clara County Housing Authority and the Central New York Planning and Development Board. Jan has a bachelor’s from Hamilton College and a master’s degree from Tufts University Center for Public Service.

Katie Fisher

Vanessa Diffenbaugh

Vanessa Diffenbaugh (she/her) joined HAF in 2024 as VP of Lending. Prior to joining HAF, Vanessa served as an Associate Director of Housing Development for MidPen Housing, where she managed a wide variety of new construction and rehab projects in the Bay Area and on the Central Coast.  A former foster parent, adoptive parent, child welfare advocate, and member of the national board of Youth Villages, Vanessa brings a unique lens to her work in housing as well as a deep belief in the transformative power of safe, affordable housing for at-risk individuals and families. She is excited to be part of an innovative team bringing new solutions to housing in the Bay Area and beyond. Vanessa has a B.A. in English and an M.A. in Education from Stanford University. When not working on housing, she can be found reading, writing, and collaborating on books and other creative projects. She is the author of the bestselling novels The Language of Flowers and We Never Asked for Wings.

Michelle Luong

Michelle (she/her) joined the Housing Accelerator Fund (HAF) in September 2024 as a Senior Loan Administrator, bringing extensive experience in commercial real estate financing, including construction and acquisition loans. With a background in loan structuring and administration developed through her work with local and regional commercial banks, Michelle is passionate about advancing housing affordability and is dedicated to supporting impactful real estate development projects across the Bay Area. Michelle holds a dual degree in Economics and Finance from Santa Clara University.

Caroline McCormack

Rigo Mendoza

Rigo (he/him) joined the Housing Accelerator Fund in March of 2023 as a Senior Financial Analyst.  He was born and raised in the East Bay and is passionate about applying his technical skills to help those impacted by housing affordability in the Bay Area. Rigo has a background in Operations, Accounting and Finance. Prior to joining the HAF, Rigo worked as a Financial Analyst for WestEd and the Public Health Institute. He received his BA in Economics from the University of California, Davis. He speaks Spanish and Portuguese.

Andrea Unsworth

Andrea (she/her) joined the HAF team in April 2025 as a Senior Financial Analyst. A proven advocate for underrepresented groups, she founded her consulting firm, which focused on operations, strategy, and finance for small businesses. Prior to joining, Andrea also worked as a municipal bond analyst for Moody’s Investors Service. Andrea has a B.A. from UCLA in Political Science and Sociology, and an MBA from USC. A California native, Andrea was born in San Diego, lived in LA for over ten years, and now resides in San Jose with her two amazing kids and a Goldendoodle named Bowie.

Kati Vastola

Born and raised in the Bay Area, Kati (she/her) is proud to be preserving its vibrancy and livability through her work at the San Francisco Housing Accelerator Fund. She joined in January 2020 to support operations, communications, and special projects. Before coming on board at the HAF, Kati served as the Regional Affairs Manager at KIPP Bay Area Public Schools, a high-performing public charter school network. She holds a BA with Honors from Brown University and an MA from UC Berkeley, both in U.S. History. When she’s not in the office, she enjoys playing soccer and hiking in the East Bay hills with her kiddo and dog.