(New York) Shares of Warner Bros. Discovery fell more than 5% on Wednesday after reports emerged that the U.S. media and entertainment giant is considering a merger with rival Paramount Global.

Warner Bros. Discovery CEO David Zaslav met with Paramount Global boss Bob Bakish for several hours to discuss the possibility of merging the two companies, according to an Axios report that cites anonymous sources. These would be preliminary discussions, the outcome of which is uncertain.

Mr. Zaslav also spoke with Shari Redstone, owner of Paramount’s parent company, about the possibility of a deal, according to Axios.

Warner Bros. Discovery includes, among others, CNN, HBO and film studios of the same name. Paramount also owns studios and includes the CBS audiovisual group in its ranks.

Mr. Zaslav and Mr. Bakish discussed how the companies could leverage each other’s strengths, such as combining their streaming services to better compete with giants Netflix and Disney , according to Axios.

As of Wednesday’s close, Warner Bros. Discovery had a market value of about $28.4 billion, more than double that of Paramount Global’s market value of about $10.3 billion.

Warner has hired bankers to study the possibility of an acquisition, according to Axios. A merger of this magnitude could lead to new concentration in the media sector and attract the attention of US regulators.