(Reuters) - Twenty-First Century Fox Inc’s shares hit a record high on Wednesday as approval for AT&T Inc’s $85 billion buyout of Time Warner Inc spurred speculation that Comcast Corp would make an offer for most of Fox’s assets.

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A firm offer from Comcast, widely expected later in the day, could upend Fox’s $52 billion all-stock deal to be bought by Walt Disney Co.

U.S. District Judge Richard Leon on Tuesday approved AT&T’s buyout of Time Warner, rebuffing an attempt by U.S. President Donald Trump to block the takeover and potentially clearing the path for more such deals in a rapidly changing media industry.

Fox shares rose 7 percent in afternoon trade. Shares of other telecom and media companies such as Sprint Corp, CBS Corp and Discovery Inc were all up between 1 percent to 3 percent. Time Warner rose almost 3 percent, while Disney was up 2 percent.

While the judge’s approval of AT&T’s deal for Time Warner may embolden Comcast, it does not guarantee clear passage for its acquisition of Fox’s entertainment business, according to antitrust lawyers.

Henry Su, an antitrust expert with Constantine Cannon LLP, said that Comcast already owns significant amounts of content because it bought NBC Universal.

Both companies operate television and film studios, have a stake in streaming service Hulu and own regional sports networks.

Craig Moffett, an analyst with MoffettNathanson, said Judge Leon’s opinion will be seen as a green light for Comcast to bid for Rupert Murdoch’s Fox, but tipped Disney as the potential winner in a bidding war.

“We continue to believe that Disney has the superior balance sheet, cost of debt, equity and rationale to emerge victorious over Comcast in a bidding war,” Moffett said.

Comcast said in May it was in advanced stages of preparing a higher all-cash offer for Fox’s assets but did not indicate the value of its bid. Reuters reported last November that both Comcast and Verizon Communications Inc had expressed interest in buying Fox’s assets.

The move by media companies to consolidate highlights the threat from online players such as Netflix Inc and Alphabet Inc’s Google, which sell content online directly to consumers, without requiring a pricey cable subscription.

AT&T’s stock, however, was down 5 percent, with analysts raising concerns about the debt the company would absorb. Research firm MoffettNathanson said AT&T will carry $249 billion of debt after the merger.

Cowen and Co analyst Gregory Williams played down the drop in AT&T’s stock price.

“Once technically driven volatility wears off we expect the stock to move higher as closure will likely provide a new investor catalyst including about $1.5 billion in anticipated cost synergies,” Williams said.