The New York attorney general's office is investigating whether internet providers are over-charging consumers for broadband speeds they advertise but never deliver. According to reports from Bloomberg and Reuters, letters were sent to three internet providers in New York last week — Verizon, Time Warner Cable, and Cablevision — asking them to disclose how they advertise internet speeds to customers and the results of any internal testing of their services.

"New Yorkers deserve the internet speeds they pay for," said attorney general Eric Schneiderman. "But it turns out, many of us may be paying for one thing and getting another. Families pay a huge cost already for internet access in New York, so I will not tolerate a situation in which they aren’t getting what they have been promised." Studies have found that internet users in New York can be charged up to 10 times more for the same high-speed internet as residents of Hong Kong, Paris, and Tokyo.

According to Bloomberg, Schneiderman's senior lawyer Tim Wu writes in the letters that he is "specifically concerned about the disruptions to the consumer experience caused by interconnection disputes." These disputes occur when one company's network joins another's, with a study last year suggesting that interconnection problems have a "severely negative impact" on internet performance. The same study notes that these difficulties are caused by disagreements between ISPs — not technical bottlenecks.

Wu, who is perhaps best known as a net neutrality advocate, and who joined the attorney general's office last month, reportedly warned Verizon, Time Warner Cable, and Cablevision that the internet speeds they offer "may deviate far enough from the speeds advertised to render the advertising deceptive." All three companies have denied that they're shortchanging customers, and have until November 8th to supply the requested material.

Updated October 26th, 9:57AM ET: Story updated to include Verizon's denial.