French carrier Iliad on Monday said it is no longer pursuing an acquisition of T-Mobile US. The top brass at Iliad, Deutsche Telekom (majority owner of T-Mobile US) and members of T-Mobile's board reportedly met to discuss a possible deal, but discussions broke down over undisclosed reasons. Iliad first put in a $15 billion all-cash bid for the carrier back in July, and later upped the offer to $36 per share.

Iliad's proposed T-Mobile acquisition always seemed like a long shot, and the U.S. carrier's executives never seemed all that interested to begin with. If the deal did wind up going through, Iliad would have owned nearly 70-percent of T-Mobile US's capital; the French carrier said its goal was to "accelerate T-Mobile US' transformation," which is an ongoing project of CEO John Legere.

T-Mobile has been at the center of plenty of acquisition talks over the past few years, including a high-profile try by Japan's SoftBank. Iliad is still holding out a sliver of hope that a deal could go through in the future, though board members of both Deutsche Telekom and T-Mobile have apparently "refused to entertain" Iliad's latest offer. Iliad maintains that a deal would have "created significant value for both Iliad's and T-Mobile US' shareholders," possibly saving $2 billion in annual costs per year.

Among the "Big Four" U.S. carriers, T-Mobile has perhaps enjoyed the most successful year in terms of mind and market share growth. CEO John Legere has introduced a number of "Un-carrier" plans and services over the last several months, giving T-Mobile an incredible amount of momentum heading into the holiday period. It has been said Deutsche Telekom is eager to ditch T-Mobile US, but after seeing the kind of year it had, perhaps the parent company is having second thoughts.

Shares of T-Mobile US are down 2.1 percent on the news.