Potential merger would reunite the two companies following their split in 2005.

National Amusements, which has a controlling stake in both the CBS Corporation and Viacom, has requested that both companies’ board of directors explore the idea of a potential merger.

National Amusements has stated that it will not accept or support any acquisition of Viacom or CBS by a third party or any transaction that would result in it surrendering its controlling position in the companies.

In terms of licensing, Nickelodeon, which is a division of Viacom, is the world’s 9th largest licensor with $5.5 billion in licensed retail sales in 2015. Paramount Pictures, which is also a division of Viacom, is No. 122 with $172 million and CBS is No. 88 with $300 million, according to License Global’s annual Top 150 Global Licensors report.

National Amusements, directly and through subsidiaries, owns roughly 80 percent of the voting shares of both Viacom and CBS and approximately 10 percent of Viacom’s total common stock outstanding.

If the two companies decide to merge, it would tentatively be an all-stock transaction in which each companies’ stockholders would receive shares in the combined company of the same class they currently hold, according to National Amusements.

Additionally, during deliberations and negotiations, Sumner M. Redstone, majority owner and chief executive officer, National Amusements; Shari E. Redstone, minority owner and president, National Amusements, and vice chairwoman, CBS Corporation; and David R. Andelman, a director on the CBS board; will not participate in the voting or any related deliberations.

More details regarding the potential merger will be announced at a later date.