Sam Altman’s brother Jack raises $275m after building HR unicorn Lattice

Jack Altman, co-founder of HR software company Lattice and brother of OpenAI chief executive Sam Altman, has raised a $275 million early-stage fund for his solo investment firm Alt Capital, the Wall Street Journal reported.

Altman told the newspaper the fund was raised in just one week, a sign of both his connections in Silicon Valley and strong investor appetite for early-stage technology deals despite broader caution in venture capital.

The $275 million vehicle marks Altman’s second fund and represents a sharp step up from the $150 million he raised in early 2024. That first pool of capital has been used to back about 20 companies, including David AI, a Y Combinator-backed start-up that builds data sets for speech models, and Owner.com, a restaurant software company that has since achieved unicorn status, according to the Wall Street Journal.

Altman said the new fund would remain focused on early-stage investments, where he believes his background as a founder can provide an edge in supporting entrepreneurs.

Founder to investor

Jack Altman launched Lattice in 2015 and built it into one of the leading players in HR software, valued at around $3 billion. He stepped down as chief executive in 2024 but continues as chairman. His experience in scaling a company from start-up to late-stage growth has bolstered his profile among founders and limited partners alike.

While his brother Sam Altman remains one of Silicon Valley’s most prominent figures through his leadership of OpenAI and previous role as president of Y Combinator, the Wall Street Journal noted that Sam is not a limited partner in the new Alt Capital fund. A third brother, Max Altman, is also active in the sector as co-founder of Saga Ventures, which raised a $125 million fund in 2024.

The Altman network

The rapid raise underlines the Altman family’s growing influence in venture capital. With Sam at the centre of the artificial intelligence boom, Max focused on growth-stage investments, and Jack building an early-stage portfolio, the brothers now straddle multiple parts of the start-up financing chain.

Jack Altman told the Wall Street Journal that the fund would continue to target areas such as AI, software and frontier technologies, sectors that remain attractive to investors even as late-stage capital tightens.

A test of delivery

The fundraising speed reflects confidence among limited partners in Altman’s judgement and network. It also suggests that, while venture capital overall remains subdued compared with the highs of 2021, select managers with operating experience and strong connections can still command large sums in record time.

The challenge now will be whether Alt Capital’s portfolio delivers returns that justify the pace and scale of its fundraising. As the Wall Street Journal observed, Altman’s bet positions him squarely in the most competitive corner of venture capital, where the difference between success and failure often lies in timing as much as strategy.