Sometime in the next two months the Federal Trade Commission will hand down its ruling on whether to embrace or reject Express Scripts' (ESRX) $29 billion acquisition of its bigger rival Medco Health Solutions (MHS). Wall Street isn't so sure the FTC will go for it, but some mergers-and-acquisit​ions pros think the agency will.

It doesn't really matter. 

Investors interested in participating in this growing health-care sector should snap up shares of both companies. Why? Usually, the stock of a company trying to acquire another company falls, while the target jumps. That's a given. But since Express Scripts announced plans to acquire Medco, the stocks of both companies have risen. Each is up 19% so far this year, with Express Script closing at $52 a share on Mar. 6 and Medco finishing at $65.

Their continued strength is one indication that investors believe the merger idea is good, if not great. And it reflects confidence that the proposed merger will get the green light. But it also signals that both Express Scripts and Medco are viable and productive enterprises -- with or without the merger.

Bret Jones of Oppenheimer is confident the proposed deal will get approval. Noting the sizable contracts that rival companies have gotten recently, Jones expects the FTC "will determine ample competition exists to allow the merger to close." And assuming the deal gets approval, "we believe the pieces fall into place for the shares to work higher." He rates the stock as "outperform."

David S. MacDonald, analyst at investment firm SunTrust Robinson Humphrey, remains bullish on Express Scripts based on the company's fourth-quarter results, which were in line with forecasts, along with its strong cash flow and continued investments pending the closing of the Medco acquisition.

"We continue to think the deal closes and ESRX remains our top health-care services pick," says MacDonald, who has a 12-month target price of $66 a share.

Should the deal get nixed by the FTC, Medco has been doing well on its own, and that's a basic reason why Express Scripts made a move on it. The catalyst for going after Medco was its anticipated loss of an $11 billon contract with UnitedHealthcare in 2013.

A combined Express Scripts-Medco will result in a "stronger competitor" in the industry, accounting for  an estimated two-thirds of U.S. adjusted prescriptions, says Herman Saftlas of S&P Capital IQ.

Bryan J. Fong, analyst at independent investment research firm Value Line, says Medco's stock has above-average long-term appeal. And if the pending deal goes through, "stockholders will realize an immediate double-digit return."