Hulu has extended its lead among virtual MVPD operators for local station sign-ups, announcing that it now has deals to retransmit 521 local broadcast affiliates across the U.S.

With the addition of more ABC and Fox affiliates this week, Hulu said it can now offer locals for each of the Big Four broadcast networks in nearly 50% of U.S. TV homes.

Offering similar price points, largely the same networks and pretty much the same features (notably, cloud DVR), vMPVDs have used access to local broadcast stations as a key differentiator.

Hulu, which is jointly owned by Fox, Disney/ABC, Comcast/NBCUniversal and Time Warner, only launched its livestreaming service in the spring of last year, but it has already assumed a dominant position in regard to vMVPDs and tie-ups with locals. AT&T’s DirecTV Now, Sony’s PlayStation Vue and Google’s YouTube TV continue to make headway, but their coverage is well below that of Hulu.

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Hulu is bundling the limited commercial version of its popular SVOD service with a package of more than 50 livestreamed cable and broadcast networks for $40 a month.

Hulu hasn’t disclosed how many subscribers it has for its livestreaming package yet, but CNBC quoted unnamed sources this week who pegged the number at around 450,000. (YouTube TV, which launched around the same time, was estimated to have about 300,000 subs.)

The market leader remains the still technically challenged Sling TV, which is estimated by analysts to have more than 2 million customers. AT&T said DirecTV Now was at 1 million late last year.