Verizon Wireless sweetened its acquisition proposal in a letter this week to the FCC, offering to divest 15 additional markets in order to advance the acquisition of Alltel.

The offer comes amid voiced analyst concerns that Verizon could walk away from the acquisition due to the economic credit crunch. Although Verizon still has enough cash to complete the deal, Alltel’s position is tenuous, as the cost of protecting its bonds from default has doubled during the crisis.

Verizon originally proposed to divest 85 markets with its original offer to acquire Alltel for $28.1 billion back in June (story here).

Verizon has volunteered to divest overlapping markets in the following states: Alabama, Arizona, Georgia, Iowa, Minnesota, Nebraska, New Mexico, North Carolina, South Carolina and Utah.

More Broadband Direct:

• Cable stocks follow market on rough ride

• Blankom lands 1st U.S. cable customer - NexHorizon

• Dish pays up on TiVo patent violation

• Xohm launch sees WiMAX-supporting products

• Time Warner Cable hires An as VP, legislative affairs

• Verizon ups divested market offer for Alltel deal

• Broadband Briefs for 10/10/08