NEW YORK (TheStreet) -- Few things can get the blood flowing on Wall Street like mergers and acquisitions. Companies with tons of cash but short on growth can have instant access to new revenue streams and addressable markets that would have otherwise taken years to build.

It would seem M&A has, indeed, become the new growth strategy in the first half of 2015. Even before the ink was dry on Avago's (AVGO - Get Report$37 billion acquisition of Broadcom (BRCM) -- at the time, the year's largest deal -- Charter Communications (CHTR - Get Reportannounced it was buying Time Warner Cable (TWC) for $78.7 billion.

It's uncertain whether another deal surpass Charter's total dollar offer before the year ends. What we do know is that there will be more deals. In Cigna (CI - Get Report), Syngenta AG (SYT) and T-Mobile (TMUS - Get Report) -- here are three companies where M&A interest is high. Here's how investors can profit from each losing its independence.

Let's look all three companies and their suitors, starting with Cigna.

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Cigna, a managed-care specialist headquartered in Connecticut, has been pursued by Anthem (ANTN), which offered Cigna $184 a share in a cash and stock deal (31% in stock). This amounted to a 35% premium to Cigna's unaffected closing price on May 28. Both companies have exchanged overtures since August 2014, yet they can't come to an agreement.

Cigna is not only being hunted, it is a hunter in its own right, having pursued Humana (HUM - Get Report), which has made it known wants to sell itself. But Humana said early Friday it agreed to a deal with rival Aetna (AET). 

These companies are eager to pair up to position themselves to respond more quickly to healthcare changes imposed under the Affordable Care Act, or Obamacare. For Cigna, which has beaten earnings estimates in five straight quarters, selling to Anthem seems like a matter of "when," not "if." Cigna may not yet agree to the terms, but it needs a deal.

In that vein, investors shouldn't be quick to exit their positions in Cigna stock, even though it appears to have run away. Though shares are up more than 56% year-to-date as of Thursday's close of $161.29, there are still potential gains ahead. On June 23, analysts at Leerink Partners raised their price target on Cigna stock to $175. And the shares still have an average buy rating and a high analyst target of $184.

Next is Swiss-based agriculture giant Syngenta, which -- since April 18 -- has been pursued by Monsanto (MON). Monsanto, the world's largest seed producer, owning some 27% market share in all seeds used in modern agricultural farming, has offered $45 billion for Syngenta, which amounts to a 43% premium to Syngenta’s unaffected closing price on April 30.

Struggling to grow revenue and profits and to offset weakness in some of Monsanto's largest segments, Monsanto is looking to Syngenta to help increase its exposure to vegetables and crops beyond its core corn and soybeans business. Syngenta is also well-diversified in technology and has a strong agriculture chemical business.

Since the offer, Syngenta stock has surged 30% to current levels of around $83. Deutsche Bank analyst Virginie Boucher-Ferte expects Monsanto to close this deal, citing Monsanto's "commitment." And this explains why Syngenta still has a consensus "Buy" rating and a high target of $108.97, suggesting investors see the stock rising 31% from current levels of around $83. So Syngenta investors may want to hang on tight for the ride.

Finally, we have T-Mobile, whose shares have skyrocketed 44% since the third-largest wireless carrier in the U.S. by market cap, began being courted by Dish Network (DISH - Get Report). While talks between both companies have been going on for more than a year, this was prior to the agreed-upon merger between AT&T (T - Get Report) and DirecTV (DTV - Get Report) -- rivals of both companies.

In others words, with a potentially larger rival on the horizon, there is now some motivation to spur this year-long dance to go beyond just talk. Though the terms of the rumored deal haven't been disclosed, it's in the interest of both Dish and T-Mobile to get something done. And with reports suggesting Dish CEO Charlie Ergen would become chairman of the combined company, while T-Mobile's chief, John Legere preside as CEO, it would seem a plan is already in place.

It seems only a matter of time before these companies tie the knot. So even with the gains T-Mobile has already amassed, investors should hold out for more. Not only does T-Mobile have an average buy rating, the price target was just raised to $46 by Citigroup analyst Michael Rollins. And if T-Mobile does reach its high analyst 12-month price target of $71, this represents 82% gains in the next 12 to 18 months over Thursday's close of $38.97.

This article is commentary by an independent contributor. At the time of publication, the author held no shares in any of the stocks mentioned.