Shares of Nextwave Wireless Inc., a San Diego holder of wireless spectrum licenses, more than doubled to 20 cents Dec. 1 on the Pink Sheets Exchange before falling back to 9 cents in heavier than usual activity.

On Nov. 30, the company announced in a securities filing that it got another extension on a deadline to arrange the necessary financing to stay afloat.

The business, which sold off its main asset, Packet Video, in two installments to Japanese telecom carrier NTT Docomo Inc. for $111 million, has been in technical default on bond payments since Aug. 1, according to filings.

Starting Aug. 1, the company entered into forbearance agreements with secured debt holders that set several deadlines to set up alternative financing packages. Those agreements have been extended twice, on Sept. 30 and Nov. 30. Its latest extension set a Dec. 15 date to find a solution.

Nextwave’s total secured debt is “substantial” by its own assessment, $983.6 million as of Oct. 1.

The company said its cash reserves are insufficient to meet its payment obligations at the current bond maturity dates. Without further accommodation from bondholders such as maturity extensions, the company may have to resort to filing for bankruptcy protection, it said in its latest filing.

For its nine months ended Oct. 1, Nextwave reported a net loss of $195.8 million, compared with a net loss of $158 million for the like period of 2010. It listed an accumulated deficit of $1.5 billion.

Traded under WAVE.PK, shares have ranged from a penny to $1.01 in the past 52 weeks.

— Mike Allen