That's the number if FISV shares directly owned by FB.
FB: 2,606,307 shares x $109.36 = roughly $285 million
JY: 415,537 shares x $109.36 = roughly $45 million
JY has been regularly selling FISV shares each month (2 homes in Malibu ain't cheap). But FB clearly holds more equity in FISV. Add to that FB's friends at New Omaha holdings/KKR owning 16% of FISV shares and it is easy to see why FB is getting his way.
FB: https://investors.fiserv.com/static-files/1c20dce1-1b2d-4123-91cc-eec837ee6aa6
JY: https://investors.fiserv.com/static-files/b9ad8675-1c87-48c9-87ba-68965d119ab9