Less than five years after the U.S. Justice Department shot down a merger of Sprint Corp (NYSE:S) and T-Mobile US Inc (NASDAQ:TMUS) on antitrust grounds, the third- and fourth-largest wireless companies are reportedly eager to give the deal another go. But prospective TMUS stock and S stock investors should sit on the sidelines while the drama plays out.

Japan’s Softbank Group Corp (OTCMKTS:SFTBF) is reportedly willing to cede its controlling interest in S to Deutsche Telekom AG (ADR) (OTCMKTS:DTEGY), which controls T-Mobile.  

SoftBank Chief Executive Masayoshi Son, spent $20.1 billion to buy a controlling stake in Sprint a few years ago. The wireless provider’s market cap now tops $36 billion, so it makes sense that the billionaire may be looking for an exit strategy.

What’s Going on With Sprint and T-Mobile?

Interestingly, news of the potential deal was leaked during the critical Federal Communications Commission spectrum auction where merger discussions are forbidden, so it remains unclear whether this is a trial balloon.

Of course, the wildcard in this mix is TMUS’ colorful CEO John Legere.

Legere certainly deserves credit for shaking up the wireless industry through innovative marketing, such as paying the early termination fees for customers who switch their service before their service contract expires.

He is far from foolish and loves the spotlight, taking delight in needling his rivals, including Sprint CEO Marcelo Claure. It would make sense that Legere would want to run a merged company. If for some reason, Legere wasn’t a top dog, he would collect a payday of nearly $65 million if TMUS were sold, according to its latest proxy.

Legere’s winning way with words can change the fact that the wireless market is becoming increasingly commoditized as new entrants, including Comcast Corporation (NASDAQ:CMCSA), Alphabet Inc’s (NASDAQ:GOOG, NASDAQ:GOOGL) Google and Charter Communications, Inc. (NASDAQ:CHTR), squeeze margins of incumbents such as T-Mobile, S, AT&T Inc. (NYSE:T) and Verizon Communications Inc. (NYSE:VZ). 

Moreover, the move to 5G isn’t going to be as easy as older technologies like 3G and 4G because it’s far more complex. Experts say 5G is expected to be three times faster than 4G, which is about four times faster than 3G. Experts don’t expect 5G to be deployed until 2019 at the earliest and wireless companies are scrambling to grab up all the spectrum they can ahead of time.

Legere would also have his hands full integrating S. While the Overland, Kansas-based company is in better financial shape now than it was in years past, it still loses money. Some analysts have accused Sprint of underinvesting in its network to bolster its bottom line, a claim that the company vehemently denies.

Bottom Line on TMUS Stock and S Stock

While odds of a merger between S stock and TMUS stock actually happening are better than they were a few years ago, let’s not forget that the new resident in the White House is no slouch in the unpredictability department either.

President Donald Trump raised a stink over the merger between AT&T and Time Warner Inc (NYSE:TWX), even though there are no obvious antitrust arguments against it. Who knows what may happen with Sprint and T-Mobile?

Given the uncertainties around the wireless industry and these two companies in particular, I am going to take a pass on shares of both potential merger partners for now. S stock and TMUS stock are trading near their 52-week highs after double-digit gains over the last year, so there is no sense of urgency for investors to make a move now.

I am not keen on VZ and T either given their appetites for high-priced content companies like TWX.

As of this writing, Jonathan Berr did not hold a position in any of the aforementioned securities.