Kansas City, Mo. ? Sprint-Nextel Corp. on Wednesday said it wanted appraisers to determine the value of shares of Nextel Partners Inc. in the event the affiliated company’s shareholders push for Sprint-Nextel to buy the company.

Reston, Va.-based Sprint-Nextel said it favored an appraisal of the affiliate’s “put options” over simply negotiating a regular acquisition price. Put options are meant to protect the value of an investment by giving shareholders the right to sell their stock at a certain price by a certain time. In this case, exercising the put rights would force Sprint-Nextel to buy the two-thirds of the shares it doesn’t already own in Nextel Partners, a Kirkland, Wash.-based affiliate which sells Nextel-branded services in 31 states.

In subsequent filings with the Securities and Exchange Commission, Sprint-Nextel criticized Nextel Partners’ basis for determining a value for its shares, saying the basis didn’t take in account future wireless technology like roaming that could lure away customers. Sprint-Nextel also said a series of similar buyouts Nextel Partners has said should be included in the valuation process are dated or, in the case of deals made during the late 1990s telecom bubble, unreliable.

Nextel Partners fired back in a filing of its own that Sprint-Nextel’s views were “inaccurate and misleading” and claimed Sprint-Nextel was trying to hurt the affiliate’s stock price and thereby reduce the cost of the acquisition.

Shares of Nextel Partners rose as much as $1.29 in early trading on the Nasdaq Stock Market on Wednesday on rumors of a possible acquisition. The stock ended up 43 cents at $26.54.

Sprint-Nextel shares gained 49 cents to $26.35 Wednesday on the New York Stock Exchange.

A special committee of Nextel Partners’ board has said it would recommend that shareholders trigger a provision in the company’s agreement with Nextel Communications Inc. to exercise the put options. The price is expected to be in the billions.

Nextel Partners must receive requests from at least 20 percent of its shareholders to hold a special meeting to vote on exercising the put rights. Such a meeting has yet to be scheduled.

The agreement calls for the two companies to appoint appraisers to determine the fair market value of the Nextel Partner shares. If the two prices differ by more than 10 percent, a third appraiser will make the final decision.

Sprint-Nextel said the process could take at least four months or longer, given the deal’s complexities.

Sprint closed its $35 billion acquisition of Nextel earlier this month, creating the nation’s No. 3 wireless company with more than 40 million wireless customers and $40 billion in annual revenue.