Clarifying the Small Business Runway Extension Ac t This bill addresses the statutory authority of the Small Business Runway Extension Act of 2018. The Small Business Administration (SBA) is subject to the Act's requirements for prescribing size standards for small businesses. The SBA must (1) issue a final rule implementing such Act by December 17, 2019, and (2) implement a transition plan to assist businesses and federal agencies in complying with the Act's requirements. The bill calculates (1) size standards for small businesses providing services on the basis of the annual average gross receipts of the business over a five-year period (currently, at least a five-year period); and (2) the size of other businesses on the basis of data over a five-year period (currently, at least a three-year period). The System for Award Management must be updated to comply with the requirements of this bill.