Wall Street was abuzz Friday over a potential merger between Sprint and Nextel, though the companies declined to comment on a slew of news reports that they were negotiating to create a combined cellular provider to rival Cingular Wireless and Verizon Wireless in size.

Numerous research analysts issued positive assessments of the potential combination of the nation’s third- and fifth- largest cellular carriers, reports of which first sprang up Thursday.

The Wall Street Journal reported Friday afternoon that Overland Park-based Sprint Corp. and Nextel Communications Inc. tentatively had agreed to a deal in which Nextel shareholders would be paid the equivalent of 1.3 shares of Sprint stock plus some cash.

As part of the deal, the combined company would spin off Sprint’s local telephone business, the Journal said, citing an unidentified person familiar the matter.

Sprint chief executive Gary Forsee would be CEO of the merged company, which would be called Sprint-Nextel, while Nextel CEO Timothy Donahue would serve as chairman, the Journal said. The company would be based in Nextel’s offices in Reston, Va., while Sprint’s Overland Park campus would serve as operations center.

The New York Times, meanwhile, citing executives involved in the talks whom it did not identify, reported Friday that in reaction to the news, Verizon Wireless held internal discussions to contemplate an offer to buy Sprint. Verizon Wireless declined comment on the reports as well.

Shares of Sprint and Nextel bobbed higher late Friday after pulling back in regular trading.

Sprint’s shares, which jumped 8 percent Thursday, rose 31 cents to $24.45 in extended trading after losing 14 cents in the regular session on the New York Stock Exchange. Nextel, which gained 7 percent Thursday, rose 29 cents to $30.05 in extended trading after dipping 5 cents in regular Nasdaq trading.

The potential appeal of a merger is apparent for both companies.

Sprint’s customer base is largely consumer, while Nextel’s is dominated by business users who tend to spend far more on their monthly bills.

Nextel — the fifth-largest wireless company and the only national cellular provider that’s an independent entity — is especially popular among mobile professionals and dispersed groups of workers who use the walkie-talkie feature on Nextel’s phones to keep in constant contact.

A merger of those operations would make the combined company a more potent rival to Cingular Wireless and Verizon Wireless by enabling the new entity to pool resources such as network capacity and cut redundant costs such as dual customer care systems and staff.

Sprint’s wireless Internet service, which it is upgrading to offer the same speeds as Verizon Wireless, would fill a major gap in the products Nextel can offer its valuable base of business users.

Together, the companies would have 40 million users on their wireless network, though not all of them would be direct customers.

Word of the potential deal comes less than two months after Cingular, a joint venture between SBC Communications Inc. and BellSouth Corp., completed its acquisition of AT&T Wireless to become the nation’s biggest cell company with 47.3 million customers.

One obstacle to a Sprint-Nextel deal might be technology, as the companies use two different wireless platforms. By contrast, a combination between Sprint and Verizon Wireless might be easier because the two companies use the same wireless technology.

Verizon Wireless, a partnership between Verizon Communications Inc. and Vodafone Group PLC, is the second-largest with about 42 million subscribers.