Drew Katz says "the turmoil of the last 10 days" has led him to abandon the planned $88 million purchase of the company Wednesday.
That leaves city philanthropist H.F. "Gerry" Lenfest the sole buyer.
The surprise announcement Tuesday comes after his father, Lewis Katz, and six others died May 31 in a crash near Boston.
Lewis Katz and Lenfest had recently bid $88 million to buy out their business partners and take over the company.
The blog BigTrial.net first reported late Tuesday that Drew Katz was pulling out of the deal.
The company also operates the Philadelphia Daily News and Philly.com website.