Earlier, shares of Charter surged more than 9 percent after a report claimed Verizon is exploring a combination with the company. The stock still ended the day 7 percent lower, while Verizon shares fell 1 percent.
There was speculation earlier that talks could be in the very early days.
Charter said it has no comment on the report. Verizon declined to comment.
Dow Jones said Thursday, citing people familiar with the matter, that the No. 1 U.S. wireless carrier is exploring a deal with Charter that would unite two giants in search of growth in a rapidly consolidating media and telecom landscape. It is unclear if Charter CEO Tom Rutledge or other top management would be open to a transaction, the report said.
The news comes amid Verizon's pending acquisition of Yahoo in a $4.8 billion deal, which has been met with hurdles after the search engine company announced two huge securities breaches.
Verizon said Tuesday in its fourth-quarter earnings release that it "continues to work with Yahoo to assess the impact of data breaches."
— CNBC's David Faber contributed to this report.