No. 5: Sean Parker

Matt Sayles

Amount donated in 2014: $550-million

Better known as the guy who helped start Napster and the founding president of Facebook, the technology entrepreneur Sean Parker is embarking on a new phase: top philanthropist.

Taking the No. 5 spot on the Philanthropy 50 list, Mr. Parker gave a total of $550-million last year to the Sean N. Parker Foundation and to his donor-advised fund, both of which he quietly established several years ago.

Until last year, the 35-year-old Mr. Parker kept a low philanthropic profile. But that changed in December when he announced a $24-million grant to establish the Sean N. Parker Center for Allergy Research at Stanford University.

The center’s researchers will not only seek to find better treatments for adults and children with allergies, said the donor, but will also work to find lasting cures to allergies.

Mr. Parker was partly motivated to award the grant because of his own experiences, he told reporters in a news conference: “I had and still to this day deal with anaphylactic allergies, so I understand firsthand how difficult it is to manage this.”

His experience with severe food allergies prompted him to find out more, and he realized there were few centers devoting much effort to finding a cure. Another motivator: He has two young children and worries they will have allergies and suffer as he has.

“Even a tiny amount of exposure to the protein in a peanut will start a cascade of events that can lead to asthma attacks, constriction of the throat, or even death,” said Mr. Parker. “I’ve been hospitalized and close to the edge many times.”

Mr. Parker has quietly supported a variety of other causes over the last decade (he gave $5-million to support Stand Up to Cancer in 2012). He said through a spokesman that he is mapping out a course for his foundation’s and his donor-advised fund’s grant-making priorities, but for now he will focus primarily on supporting the life sciences.