Wiktionary
n. (context legal US English) In the United States, a law that regulates the offering and sale of securities to protect the public from fraud, requiring the registration of all securities offerings and sales, as well as of stock brokers and brokerage firms.
WordNet
n. a state law regulating the sale of securities in an attempt to control the sale of securities in fraudulent enterprises
Wikipedia
A blue sky law is a state law in the United States that regulates the offering and sale of securities to protect the public from fraud. Though the specific provisions of these laws vary among states, they all require the registration of all securities offerings and sales, as well as of stockbrokers and brokerage firms. Each state's blue sky law is administered by its appropriate regulatory agency, and most also provide private causes of action for private investors who have been injured by securities fraud.
The first blue sky law was enacted in Kansas in 1911 at the urging of its banking commissioner, Joseph Norman Dolley, and served as a model for similar statutes in other states. Between 1911 and 1933, 47 states adopted blue-sky statutes (Nevada was the lone holdout). Today, the blue sky laws of 40 of the 50 states are patterned after the Uniform Securities Act of 1956. Historically, the federal securities laws and the state blue sky laws complemented and often duplicated one another. Much of the duplication, especially with regards to registration of securities and the regulation of brokers and advisors, was largely preempted by the Securities and Exchange Commission with the National Securities Markets Improvement Act of 1996 (NSMIA). This act, however, left some regulation of investment advisors and much of the fraud litigation under state jurisdiction. In 1998, state law securities fraud claims were expressly preempted by the Securities Litigation Uniform Standards Act from being raised in lawsuits that were effectively class actions by investors, even if not filed as class actions.