After AT&T (T) finally pulled its bid for T-Mobile as a result of regulatory concerns related to market share, the mobile network operator is left looking for other suitors. As part of the agreement, AT&T will have to pay T-Mobile's parent, Deutsche Telekom, a breakup fee of $3 billion in cash and an additional $1 billion worth of spectrum and other assets.

While spectrum and roaming agreements will benefit T-Mobile from a network coverage standpoint, we do not expect that Deutsche Telekom will invest the $3 billion in the U.S. carrier, given its plans to exit the market. Although a portion will certainly be used to cover some of the struggling company's expenses.

Instead we believe Deutsche Telekom will look for other suitors, possibly trying to revive discussions with Sprint (S), or break T-Mobile up and sell off its assets.

Before AT&T's surprising bid back in March, Deutsche Telekom was rumored to be in discussions with Sprint about a potential T-Mobile merger. While this arrangement could be revisited, Sprint is in a much more precarious position now, given its increased debt load and margin-crushing iPhone deal. Deutsche Telekom would likely be forced to accept a stock-heavy deal, with no guarantee that the deal would be approved by regulators. Although we expect the topic to be broached between the two parties, it seems much less feasible at this point than it did the first time around.

If Deutsche Telekom is dead set against staying in the U.S. market, its best option may be to gradually sell off T-Mobile's assets, such as its wireless towers, separately. This would expand the list of potential bidders and avoid regulatory headaches.

In the absence of a breakup or sale, the company could pursue network-sharing agreements with smaller players such as Leap or MetroPCS, or wholesalers such as Clearwire or Lightsquared (which would bring their own financial/regulatory​ baggage to the table). In any event, none of these options are nearly as appealing to Deutsche Telekom and its shareholders as the AT&T deal.

One more possibility is a partnership with Dish Network (DISH), which has been acquiring wireless spectrum and wants to bundle its video services with a voice and data network. Because Dish does not operate in the wireless market, such a partnership, or even an eventual merger, would be much more likely to pass regulatory muster (see our previous article Dish Could be a Key Beneficiary of AT&T's Hunt for Spectrum).