AT&T's $85.4 billion deal to acquire Time Warner is likely to face some of the toughest regulatory scrutiny in recent U.S. history of mergers and acquisitions. Opposition and calls for Washington regulatory review, surfaced soon after the deal was announced to combine AT&T's ( T ) broad communications reach with Time Warner's ( TWX ) array of premium entertainment and media content. Time Warner's shares fell 3.1% Monday to close at $86.74, below the $107.50 offered by AT&T, reflecting Wall Street's concern about a deal winning regulatory approval. It's unusual for the shares of an acquisition target to fall after a deal is announced. AT&T shares slipped 1.7% to close at $36.86. AT&T and Time Warner say the deal represents the next step in a broad convergence of media and communications, and would let consumers get premium content like the popular HBO network however they want it.