Aug 14 (Reuters) - Billionaire investor Mario Gabelli's investment fund filed a class-action lawsuit on behalf of Paramount Global shareholders alleging the company's controlling shareholder, Shari Redstone, benefited unfairly at their expense in the $8.4-billion merger with Skydance Media, according to a statement from Gabelli's firm.

Gabelli Value 25 Fund and affiliates alleged that Redstone's investment vehicle, National Amusements (NAI), received $60 for each of its Class A Paramount shares while public shareholders only received $23, according to a statement from Gabelli's GAMCO Investors.

The lawsuit named as defendants National Amusements, which is now known as Harbor Lights Entertainment, Paramount Global board members, Redstone, and Skydance.

A representative of Redstone declined to comment, and Skydance did not immediately respond to a request for comment on the lawsuit, which was filed under seal on Wednesday in Delaware's Court of Chancery.

GAMCO said it had an obligation to pursue the lawsuit on behalf of its clients. "GAMCO voiced its concerns early in the process and asked at minimum for more transparency regarding what NAI was receiving for its identical Paramount voting shares," said a statement from Christopher Marangi, co-CIO, Value, of GAMCO Investors. He said GAMCO was forced to redeem its shares for cash.

The drawn-out deal with Skydance closed on August 7, creating the Paramount Skydance Corp PSKY.O. The merger combines Paramount's sprawling global distribution network and prized film and TV library with Skydance's production and technological capabilities.

GAMCO was listed in Paramount's 2025 proxy statement as the second-largest shareholder with 11.7% of the company's Class A stock.

Marangi said Paramount ignored GAMCO's concerns and did not put the deal to a vote of minority investors, as it said was customary.

(Reporting by Tom Hals in Wilmington, Delaware, and Jaspreet Singh in BengaluruEditing by Rod Nickel)

((thomas.hals@thomsonreuters.com; 610-544-2712))