Tuesday’s court ruling that AT&T Inc. can proceed with its nearly $85 billion acquisition of Time Warner Inc. could open the floodgates to a wave of mega-mergers, and investors wasted no time in betting on the future.

Shares of AT&T T, -2.24% slumped 5% in morning trade Wednesday, putting them on track to snap a six-session win streak, while Time Warner shares US:TWX jumped 2.8% to head toward a near eight-month high.