I ran a quick search for US Patents and published US Patent Applications that include the words “smart contract.” Recently I did the same thing for bitcoin/blockchain. Unlike with bitcoin/blockchain, which have a considerable amount of filings to their name, smart contracts only show up in seven published US Patent Applications, and zero US Patents have been granted directed toward smart contracts.
Taking a quick look through these filings they do in fact seem to deal with smart contracts at varying levels. One filing appears to cover trade matching, clearing, and settlement by using a decentralized exchange. Another filing focuses on using sidechains to assist in due diligence for deals.
Even though as of July 21st, 2016, there are only seven published US Patent Applications that number is sure to rise. If the upward trend in filings that bitcoin/blockchain has seen is any indicator patent filings directed towards smart contracts will greatly increase within two years or so.