Cointelegraph reports the SEC letters to possibly hundreds of crypto-companies, but also reports FinCEN has simultaneously ruled exchanges and payment processors most likely fall under the US definition of money transmitter and thus, must apply for licenses.

http://cointelegraph.com/news/112811/us-regulators-one-two-punch-sec-probes-crowdsales-fincen-takes-aim-at-exchanges

You can read the FinCEN rulings at these links.

http://www.fincen.gov/news_room/rp/rulings/pdf/FIN-2014-R011.pdf

http://www.fincen.gov/news_room/rp/rulings/pdf/FIN-2014-R012.pdf