The Bill and Melinda Gates Foundation is beefing up investments in private biotechnology companies, signaling what the Financial Times sees as a shift in the philanthropy’s approach to tackling disease.

Trevor Mundel, the chief of global health for Gates, described plans for the foundation to take equity stakes worth several million dollars in up to a dozen biotech firms working on vaccines and other treatments for infectious diseases affecting the world’s poor.

To maximize returns, the Seattle-based foundation — the world’s largest philanthropy — has softened its longtime policy on investing endowment funds to support specific programs. According to the Times, its objective in backing fledgling biotech outfits is to influence firms pursuing promising treatments and negotiate low-cost access to those remedies for poor countries.

“We will make the investment and not ask for a return but for global access,” Mr. Mundel said. “We will specify the countries and the diseases.”