On Thursday, four US senators, led by Bernie Sanders (I-Vt.), asked the Federal Communications Commission (FCC) to investigate how cable and broadband providers are charging their customers.

In a letter to FCC Chairman Tom Wheeler, Sanders wrote that only 37 percent of Americans “have more than one option for high-speed broadband providers.” Because of the de facto monopoly situation in much of the country, cable and broadband providers “are able to charge ridiculous prices and add hidden fees onto a customer’s bill,” Sanders added in a press release.

The letter—also signed by Senators Elizabeth Warren (D-Mass.), Edward Markey (D-Mass.), and Al Franken (D-Minn.)—says that gathering pricing information takes new urgency after Charter Communications' recent proposal to buy Time Warner Cable. In their letter, the senators specifically call out Time Warner Cable for dubious pricing schemes:

In addition to steeply rising prices, consumers are often unaware of the various fees that are tacked onto their monthly bills because of the lack of transparency in pricing. To cite just one example, Time Warner Cable began charging a cable modem rental fee in 2012 of $3.95 a month. TWC then raised the price to $5.99 a month in 2013. Today it charges $8 a month, a 203 percent increase in three years' time, in addition to monthly broadband charges.

A Time Warner Cable spokesperson commented on the fees cited by the senators in a comment to Ars: "TWC provides its customers with advance notification of any price increases. Every TWC Internet customer can choose to avoid the modem lease fee by purchasing one of growing number of compatible modems at retail."

The senators ask only that the FCC gather information on pricing—they did not ask the Commission to take any action. “At the very least, Americans should be able to understand the price of the product they are buying and what their neighbors are paying for the same service,” the letter says.

The letter notes that the FCC has a duty to promote the deployment of broadband (although its members are in disagreement over whether Internet access is a necessity or not). The Commission's recent net neutrality order has expanded its power to look into whether customers are being treated fairly by their cable and broadband providers. Earlier this year, Ars spoke to two customers who complained about broadband pricing to the FCC and saw their rates lowered just a few days after they filed the compliant.