John William Nelson (@nelsonjohnw) writes on where law and technology intersect in the blog Lex Technologia. His post helps to answer the question as to whether or not securities laws in the U.S. apply to Bitcoin:
No entity or assets back up Bitcoin value. Bitcoin value is entirely virtual—a Bitcoin is only worth what another person thinks its worth. This is different than currency issued by countries.
Bitcoin is backed by no entity, no commodity, no organization. Bitcoin value is not based on government regulation or law mandating its use in a country.
Bitcoin investors should absolutely worry about securities laws. The securities definitions outlined above might not apply to Bitcoins themselves, but they are flexible enough to apply to Bitcoin exchanges that convert a Bitcoin to real-world currencies.
Securities law is broad enough to potentially capture any enterprise where investment for profit is involved.