This subpart provides rules for setting and adjusting rates of basic pay for senior-level (SL) and scientific or professional (ST) employees under 5 U.S.C. § 5376. Section 5376, as amended by section 2 of the Senior Professional Performance Act of 2008 (Pub. L. 110-372, October 8, 2008), promotes performance-based pay by enabling an agency that attains certification of a performance appraisal system covering senior professionals to fix rates of basic pay for those employees up to the rate payable for level II of the Executive Schedule. Under 5 U.S.C. § 5307(d) and subpart D of part 430 of this chapter, the Office of Personnel Management (OPM), with Office of Management and Budget (OMB) concurrence, grants certification only to a performance appraisal system that, in its design and application, makes meaningful distinctions based upon relative performance. This subpart implements the purpose of the law by providing for pay determinations for SL and ST employees to be based on individual performance, contributions to the agency’s performance, or both, as determined through administration of the agency’s performance management system(s) for SL and ST employees.