Small Business Mergers, Acquisitions, Sales, and Brokerage Simplification Act of 2018 This bill amends the Securities Exchange Act of 1934 to exempt from that Act's registration requirements merger-and-acquisition brokers that facilitate transfer of ownership in privately held companies with earnings or revenues under a specified threshold. This exemption shall not apply, however, to brokers that: receive, hold, transmit, or have custody of funds or securities to be exchanged by parties to an ownership transfer; engage on behalf of an issuer in a public offering of registered securities; engage on behalf of any party in a transaction involving specified shell companies; provide financing related to the transfer of ownership; assist any party to obtain financing from a third party in specified circumstances; represent both buyer and seller without disclosure and consent from both parties; facilitate a transaction with a group of buyers formed with the assistance of the broker; engage in transferring ownership to a passive buyer; bind a party to a transfer of ownership; or are subject to suspension or revocation of registration or to other specified disqualifications.