Silicon Valley stalwart Andreessen Horowitz is launching a novel effort to boost diversity in technology: an exclusive new fund targeted at black celebrities, athletes and media figures.

Basketball star Kevin Durant, actor Will Smith and Essence magazine publisher Richelieu Dennis are among the initial limited partners in the venture-capital fund, according to people familiar with the matter.

The fund will be relatively small, totaling roughly $15 million, and will invest alongside Andreessen Horowitz’s main $1.5 billion fund, according to people familiar with the matter. While investors will profit if the fund performs well, Andreessen Horowitz has said it won’t collect the proceeds it would normally generate from fees and carried interest. Instead, the firm will donate that money to nonprofits aimed at boosting the involvement of blacks in technology, those people said.

Other details of the fund, including the number of limited partners and how they were chosen, weren’t clear in part because it still hasn’t closed. An Andreessen Horowitz spokeswoman declined to comment.

Mr. Dennis, founder and executive chairman of Sundial brands and Essence Ventures, said he decided to invest in the fund, which is called “Culture,” because of its aim to help get more people of color into technology.