Clearwire revealed that last week it received a written offer for some of its spectrum from a “strategic buyer”, ahead of its planned acquisition by shareholder Sprint.

In a regulatory filing, the troubled US wholesale operator said that it had received an offer for spectrum leases generally covering large markets, for “a gross price of approximately $1.0 billion to $1.5 billion, the present value of the spectrum leases which could be substantial”. The potential buyer was identified only as “Party J”.

It said that its special committee and advisors will “evaluate this proposal and any other proposal and engage in discussions with each of Party J and Sprint, as appropriate”.

This is not the first time that Clearwire has come into the sights of another perspective suitor. Media company Dish Network made a bid which outstripped that of Sprint, although at the time it was noted that it faced a number of hurdles – not least that as Clearwire’s biggest shareholder, Sprint would need to green-light the deal.

Sprint noted in the same filing that the special committee will “continue to evaluate the Dish proposal and engage in discussions with each of Dish and Sprint, as appropriate”.

Clearwire said that it had engaged in a wide-ranging review of its strategic options previously, but that there were “limited strategic alternatives available” due to Sprint not being willing to sell its existing holding, and “various restrictions contained in the organisational documents of Clearwire”.

The Sprint deal is not without its critics. Last week Crest Financial, which describes itself as “the largest minority shareholder of Clearwire”, filed a proxy statement which “will be used to urge Clearwire stockholders to reject the proposed merger with Sprint”.

Crest argues that it would be better for Clearwire to remain a standalone company, because Sprint’s offer is “inadequate – based on several measures – and was devised in a way that unfairly disadvantages minority stockholders”.

Reuters also noted that Clearwire had said in the document that it is “actively considering” whether to miss a 1 June 2013 interest payment on $4.5 billion worth of debt.