CenturyLink and Level 3 Communications may have an urge to merge. Image source: Getty Images.

What happened

Shares of communications services companies CenturyLink (NYSE:LUMN) and Level 3 Communications (NYSE:LVLT) both soared in Thursday trading -- and we're not just picking those two names at random out of a grab bag of big gainers for the day. CenturyLink shares closed up 9.7% for the day, and Level 3 up 10.6%, after retracing some of their gains earlier in the day. These two particular companies, you see, are linked -- or rather, they may be about to become so.

According to multiple media reports, CenturyLink and Level 3 are in "advanced talks" to merge their businesses in a deal worth in excess of $50 billion, including both the market capitalizations of both companies and the value of their respective debts. Neither company is talking about the speculated merger, but confirmation of the deal (or its refutation) is expected as early as next week.

So what

This deal, if it comes to pass, will be an example of vertical integration in the communications space. Fiber network operator Level 3 is well known as an upstream provider of "enterprise level" communications services to businesses. Downstream, CenturyLink links up individual customers to the global internet through broadband and phone-service offerings. That being the case, investors should expect to be regaled with promises from corporate management of significant cost-saving "synergies" from such a merger in an effort to garner support for the deal.

Now what

With shareholders in each stock having already netted 10% profits on the mere rumor that a deal is in the works, they may not need much more convincing to OK the merger. After all, if the merger fails to materialize, those gains would likely evaporate.

As for investors who weren't lucky enough to own the stocks prior to the news coming out, well, CenturyLink shares currently sell for just 17.4 times earnings -- about a 30% discount to the 25.1 times earnings valuation at Level 3. If this turns out to be a "merger of equals," therefore, then it's more likely there are more gains in store for owners of CenturyLink stock than for shareholders in Level 3.

On the other hand, according to analysts polled on Yahoo! Finance, both of these companies are currently expected to experience declining earnings over the next five years. That being the case, it's hard to argue that either stock was any sort of a bargain prior to their respective run-ups in price -- and even less so afterwards.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.