Longtime Paramount Global shareholder Mario Gabelli is stepping up his campaign for more transparency around the company's merger deal with Skydance.

Billionaire investor Mario Gabelli still has not decided whether he'll mount a legal challenge to Skydance Media's merger with Paramount Global. Gabelli is the founder, chairman and CEO of GAMCO Investors,

Gabelli requested the delay so that he could probe for “potential fiduciary and/or federal securities violations” against Paramount's minority shareholders.

The FCC filing follows legal maneuvering from Mario Gabelli, the largest holder of nonvoting shares, seeking access to Paramount's books.

The letter comes after the GAMCO Investors Inc. chairman filed a books and records request seeking more specifics about the $8 billion merger deal