Marc Andreessen, co-founder of Netscape Communications Corporation, and his wife, Laura Arrillaga-Andreessen, have announced a $27.5-million gift to Stanford University Hospital & Clinics in Palo Alto, Calif., reports The Wall Street Journal.

Mr. Andreessen, 36, made his fortune on the 1998 sale of Netscape to AOL that yielded $4.2-billion in stock. He also sold another software company that he had co-founded, Opsware, to the Hewlett Packard Company for $1.6-billion this summer.

Part of the couple’s motivation for giving is that Mr. Andreessen was pleased with the services he received as a patient of Stanford hospital in the late 1990s.

The couple’s connection to charitable activity at Stanford runs deeper than that, however. Ms. Arrillaga-Andreessen is a Stanford alumna who teaches philanthropy at the university, and her father, John Arrillaga, a real-estate developer, gave Stanford $100-million in 2006.

In explaining why he and his wife made the gift, Mr. Andreessen said, “At a certain point, you can spend it, you can give it to your kids, which we don’t think makes sense, you can let the government take it ultimately in taxes, or you can give it away.” He said the choice was simple: “Of the four options, it’s the obvious thing to do.”