Today Senators Edward Markey, Richard Blumenthal, and Ron Wyden sent a letter addressed to the heads of AT&T, Verizon, Sprint, and T-Mobile, asking them explanation about allegations they've been throttling video services. The senators' letters said that the Wehe tests "indicated throttling on AT&T for YouTube, Netflix, and NBC Sports... throttling on Verizon for Amazon Prime, YouTube, and Netflix... throttling on Sprint for YouTube, Netflix, Amazon Prime, and Skype Video calls... [and] delayed throttling, or boosting, on T-Mobile for Netflix, NBC Sports, and Amazon Prime by providing un-throttled streaming at the beginning of the connection, and then subsequently throttling the connection". According to Ars Technica, Sprint denied Skype throttling and AT&T questioned the accuracy of the Wehe tests. The wireless carriers have until 6 of December to answer the questions for the senators.