(Reuters) - Shares in ViacomCBS and Discovery Inc tumbled on Wednesday, pausing a rally that has seen the stocks soar this year on increased appetite for value names, newly launched streaming services and an unwinding of bearish investor bets. ViacomCBS Class B shares last traded down 4.4% at $92.02 after hitting a record of $101.97 on March 15. Discovery shares last traded down 3.6% at $73.09 after hitting a high of $76.61 on Tuesday. ViacomCBS and Discovery have gained 146% and 142% year-to-date, respectively, as investors piled into undervalued names on expectations of a broader reopening of the U.S. economy while also eyeing direct-to-consumer streaming services that could help the more traditional media companies compete against newer rivals. Shares of the companies were also boosted by investors who had bet against the stock, now being forced to unwind their positions in the face of a rising stock price, said Chris Marangi, co-chief investment officer for value at Gabelli Funds, which was Viacom’s second biggest holder of voting stock as of late January with 7.88% of Class A shares. A similar phenomenon, known as a short squeeze, helped spark a wild ride in shares of GameStop Corp and other names popular with retail traders on Reddit’s WallStreetBets and other online forums in January. “Viacom was a beneficiary of the early stages of the GameStop short-covering frenzy, as there was short covering across the market,” Marangi said. The number of Discovery Class A shares shorted have more than halved since mid-January and stood at 40.5 million on March 16, according to FIS Astec Analytics data. Some 81.1 million Viacom shares are shorted compared to 96.4 million in January, the firm’s data showed. Along with an increasing appetite for value stocks broadly, Mirangi also cited interest in recent launches of ViacomCBS’s Paramount+ and Discovery’s Discovery+ streaming video services as both companies should benefit from a direct relationship with consumers. They are following in the footsteps of Walt Disney Co’s hugely successful launch of Disney plus in Nov. 2019. He noted that media stocks such as ViacomCBS and Discovery underperformed for years as investors felt they were “just going to milk cashflow from the dying traditional media bundle.” “The stocks have very quickly made up for several years of underperformance,” said Marangi. “From here its about execution and that will take several years.”