T-Mobile is rejecting Iliad’s surprise bid to buy out the carrier, according to the Wall Street Journal.

The U.S.’s fourth largest carrier reportedly doesn’t Iliad’s $15 billion bid is an attractive enough valuation and is declining to open its books so the French carrier can perform due diligence.

One of the Journal’s sources said the offer was “dead in the water” but another source wasn’t as confident that T-Mobile had dismissed the deal and didn’t know if Iliad was planning on revising its bid.

But Reuters is reporting that Iliad is already reaching out to other investors in an attempt to sweeten the deal. The carrier has reportedly talked with Dish Network, Cox Communications and Charter Communications, all of whom could be interested in jumping into the mobile market. Dish in particular has a large amount of spectrum it needs to put to use and no network on which to deploy it.

Iliad’s attempt to acquire a 56.6-percent stake in T-Mobile came as months of reports that Sprint was working on a bid for a controlling stake in T-Mobile. No official announcement of that transaction has come from either camp but it’s believed that SoftBank—which owns 80 percent of Sprint—has lined up financing and was discussing the deal with Deutsche Telekom, which owns 67 percent of T-Mobile.

U.S. regulators could find it easier to approve an Iliad acquisition of T-Mobile rather than watching two U.S. rivals merge and shrink the competitive landscape. In addition to the skepticism regulators have aimed at the potential Sprint-T-Mobile merger, the FCC recently said it was against those two carriers forming a joint venture in order to bid in the upcoming 600 MHz incentive auctions.