Andrew Baggarly on Twitter: Buster Posey turned down almost $30 million by retiring (and opting out of 2020), but he's made loads off endorsements/investments (Body Armor was a major windfall) and now
Buster Posey joins Giants ownership group - The Athletic
Buster Posey joins Giants ownership group
Logan Webb on Buster Posey joining the ownership group: When Buster's around it's different
Buster Posey Joins San Francisco Giants Ownership Group - The New York Times
Buster Posey announces retirement
Buster Posey Joins San Francisco Giants Ownership Group - The New York Times
Buster Posey honored by Giants
How Buster Posey impacted this SF Giants catcher with 45-min phone call
Buster Posey buys stake in San Francisco Giants - San Francisco Business Times
Buster Posey joins San Francisco Giants ownership group - CBS San Francisco