CBS could follow online video pioneer Hulu with an ad-free version of its own over-the-top service CBS All Access, charging an additional $4 per month on top of the $5.99 monthly fee the broadcaster gets for the offering.

On a conference call with analysts to discuss fourth quarter results, CBS chairman and CEO Les Moonves said nothing is carved in stone, but that the company is considering offering an ad-free version of CBS All-Access.

“We’re exploring it,” Moonves said on the call. “We’re not there yet.”

He added that the ad-free offering “hasn’t worked quite well” for Hulu so far.

Hulu launched the ad free version in September, charging an additional $4 per month on top of its $7.99 monthly charge for the service. The online service continues to offer its original service which includes ads for $7.99 per month.

CBS launched CBS All-Access in October 2014, and Moonves said the service received a boost in customers after it aired a commercial during the Super Bowl. Although CBS would not say how many customers the service has, it did say that it is attracting a younger demographic.

CBS has been developing new programming for the All Access service – its new Star Trek television series will appear exclusively on the service after its first episode debuts in January 2017 on the broadcast network. Moonves added on the call that its own CBS Studios could create additional programming for the OTT service.