ABS-CBN Corp.’s shares are headed to a 10-year low after Philippine President Rodrigo R. Duterte continued his attacks on the television network he has accused of bias, urging its owners to sell before its franchise expires in March.

Shares of the media company dropped as much as 6.3% on the first trading day in Manila this year, poised for its lowest close since March 2009. The stock ended 2019 with a 21% loss compared with the local benchmark index’s 4.7% gain for the year.

In a televised speech on Dec. 30, Mr. Duterte suggested the media firm’s franchise renewal is uncertain. He had earlier threatened to block the network’s bid to extend the franchise for 25 years. ABS-CBN has not issued a statement about Duterte’s remarks, a spokesman said.

“Your contract is expiring. I’m not sure what will happen if you renew,” Mr. Duterte said. “If I were you, I would just sell.”

The president has accused ABS-CBN as well as privately owned Philippine Daily Inquirer of unfair reporting, allegations that the media companies have denied.

Mr. Duterte also resumed his criticism of water utilities for alleged corruption in his Dec. 30 speech, threatening to sue and jail the owners of Manila Water Co. and Maynilad Water Services, Inc. He reiterated a plan for a military takeover of the water utilities’ operations.

Manila Water of Ayala Corp. and Maynilad owners Metro Pacific Investments Corp. and DMCI Holdings, Inc. are among the worst-performing Philippine stocks in 2019, plunging since early December when Mr. Duterte started his censure.

“For those of you asking where are the big fish in my fight against corruption, I’ll deliver them: Ayala and Pangilinan,” he said. “If they do something wrong, I’ll really jail them,” Mr. Duterte said, referring to the family of Jaime Augusto Zobel de Ayala, which owns Manila Water and Manuel V. Pangilinan, who chairs Metro Pacific.

The two tycoons did not immediately respond to requests for comments.

Manila Water plunged 14% in early Thursday. Metro Pacific was down 4.3%, while DMCI tumbled 3.9%. — Bloomberg