Five music industry heavyweights have confirmed plans to form a 24-hour music channel that some insiders see as the first real challenger to MTV.EMI, Polygram, Sony Software, Warner Music Group and Ticketmaster announced Monday that they will form a partnership to operate an advertiser supported, video music channel to be launched in the U.S. and Puerto Rico (Daily Variety, Jan. 31). The unnamed vidchannel is expected to bow in the U.S. in the fourth quarter this year with the Puerto Rico launch by early ’95. The companies will seek other partners, expected to be cable TV operators or multiple system operators, to further the venture. The new channel is seen as the first real challenge to the hold on musicvideo programming that MTV has enjoyed for more than a decade. But MTV execs downplay the effect the new channel will have, saying they welcome “any fair competition.” Exclusivity issues MTV is said to be concerned about exclusivity. The channel fears the new vidchannel backers may withhold their labels’ artists from MTV until they appear first on the new channel. MTV Networks president Tom Freston, according to sources, already has had a round of talks with the principals in an effort to establish some working ground rules before the launch. Sources said Monday’s announcement was accelerated in part by recent press reports of the venture. The formal acknowledgment also was designed to get cable multisystem operators to start talks with the new entity. Reps for the five companies declined comment.