expressed concern

Prices for phone text messages have risen 100 percent in the last three years, and Congress wants to know why.

In a letter to the top four wireless providers this week, Sen. Herb Kohl (D-Wis.) asked for their answers by Oct. 6.

'Identical Price Increases'

Text-message prices have climbed from 10 cents per message to 20 cents in three years while the carriers' costs for sending and receiving messages has reportedly decreased. The four major carriers, which some analysts say control nearly 90 percent of the market, have raised prices at nearly the same time.