Sinclair Broadcast Group will partner with the owner of The Weather Channel to buy 21 regional sports networks and Fox College Sports from The Walt Disney Co. for $10.6 billion, the companies announced Friday.The deal further transforms Hunt Valley-based Sinclair, which grew from Baltimore’s WBFF Fox45 in 1971 into the nation’s largest owner of broadcast television stations. It also marks a remarkable turn of fortunes for the company that just last summer lost a bid to buy Tribune Media and extend its reach even further.The company’s shares spiked in after-hours trading, surging more than 15 percent to $51.86 each after closing Friday at $44.95 before the deal was announced.The Fox regional sports networks, which generated $3.8 billion in revenues across 74 million subscribers last year, make up the largest collection of such channels in the market and include exclusive local rights to 42 professional baseball, basketball and hockey teams. The purchase price will be $9.6 billion after adjusting for minority equity interests.The portfolio excludes the YES Network, which is being acquired separately by the New York Yankees with Sinclair as a minority partner, according to a report in The Wall Street Journal.Sinclair is forming a wholly owned subsidiary, Diamond Sports Group LLC, with Byron Allen, founder, chairman, and CEO of Entertainment Studios, to acquire the sports networks. The deal will require U.S. Justice Department approval. Allen, whose Los Angeles-based firm bought the Weather Channel last year, will become an equity and content partner in Diamond.“While consumer viewing habits have shifted, the tradition of watching live sports and news remains ingrained in our culture,” said Chris Ripley, Sinclair’s president and CEO, in an announcement. “As one of the largest local news producers in the country and an experienced producer of sports content, we are ideally positioned to transfer our skills to deliver and expand our focus on greater premium sports programming.”Ripley said the deal will help Sinclair diversify its content and revenues streams through networks that drive live viewing.“This is illustrative of Sinclair’s desire to be a bigger content player,” said Patrice Cucinello, a director at Fitch Ratings in New York. “They’re going big in broadcast and sports, and sports is becoming increasingly important in the ecosystem to maintain viewership.”She said she views Sinclair’s heavier investments in sports as a positive.“Broadcast ratings and viewership will remain challenged over the near and longer-term and live events and sports are becoming increasingly important as emerging entertainment choices come online,” Cucinello said.The deal will give the broadcaster steady revenue and fit well with its other moves into sports programming, Tuna Amobi, an equity analyst at CRFA Research, said in a report Friday.“With regional footprints that traverse several major U.S. markets, the [sports networks] had been expected to fetch a much higher valuation, after a seemingly competitive months-long auction that attracted several other potential bidders,” Amobi wrote. “We think the [networks] could provide another complementary backdrop for [Sinclair’s] recent forays into sports programming,” through both traditional and online channels.Amobi noted that regional sports networks have been losing viewers as more pay-TV customers cut the cord.Still, “we see a relatively steady dual revenue stream (subscription and advertising) that could bode well for Sinclair's long-term return on investment,” he wrote.Sinclair also owns professional wrestling’s Ring of Honor and acquired the Tennis Channel in 2016. The broadcaster said in January that it will launch a regional sports network with the Chicago Cubs. Sinclair also owns Stadium, a joint venture focused on college sports and professional highlights, and offers high school sports programming.Disney, which acquired 21st Century Fox’s entertainment business for $71 billion in March, needs to spin off the sports networks as a condition of securing U.S. antitrust approval for that deal. Disney agreed to sell the sports networks within 90 days because it owns ESPN. (Fox is keeping Fox News, Fox Business, Fox Sports and the Fox TV network.)Fox Business has reported that other bidders in the auction for Disney’s sports networks included Liberty Media, led by cable magnate John Malone, and the Big3 Basketball league, led by businessman and hip-hop legend Ice Cube. Major League Baseball reportedly partnered with Liberty Media on its bid. And Ice Cube recently announced via Twitter that Magic Johnson joined his bid.Sinclair’s newly acquired portfolio will include exclusive local rights to 14 Major League Baseball teams, 16 National Basketball Association teams, and 12 National Hockey League teams. Among the networks are Fox Sports Arizona, Fox Sports Detroit, Fox Sports Florida, Fox Sports Ohio and Fox Sports San Diego, among others.Sinclair had been building cash on its balance sheet in the wake of its failed $3.9 billion Tribune bid. The merger of the two media giants ran into trouble after Federal Communications Commission Commissioner Ajit Pai raised concerns about whether the deal was in the public interest. The proposed merger had drawn criticism from across the political spectrum for giving Sinclair unprecedented access to so much of the nation’s airwaves, which critics said would limit broadcast market competition and diversity.Sinclair’s planned acquisition from Disney continues consolidation in the broadcast and cable industries, said Mark Feldstein, the Richard Eaton Chair of Broadcast Journalism at the Philip Merrill College of Journalism at the University of Maryland. Feldstein said Sinclair’s latest move is concerning even though it involves sports networks instead of local TV stations and their news programming.“The country’s biggest broadcaster now is even bigger,” he said. “The python continues to swallow up smaller critters. … Monopolization is still a bad thing even outside of news.”The Hunt Valley company said it will capitalize the Diamond subsidiary with $1.4 billion in equity, made up of cash on hand and new debt at Sinclair Television Group. It will also fund the purchase with $1 billion of privately placed preferred equity of a newly formed wholly owned subsidiary of Sinclair and parent of the RSN Holding Co. The rest of the purchase price will be funded by $8.2 billion of fully committed secured and unsecured debt incurred by Diamond. The boards of both Sinclair and Disney approved the deal.