To Advance Their Cause, Foundations Buy Stocks

Earlier this year, the Bill & Melinda Gates Foundation invested $10 million to acquire a stake in Liquidia Technologies, a biotechnology company working on new ways to deliver vaccines.

A growing number of foundations are using such investments, known as P.R.I.’s, to connect with profit-making ventures that advance their missions. But as they become more popular, some officials in the nonprofit field worry that this and other newer mechanisms are blurring the lines between profit-making businesses and charitable work.