Expand All 6510. Applicability 6520. Operation of the Service 6530. OTCBB-Eligible Securities 6540. Requirements Applicable to Market Makers 6541. Reserved 6550. Transaction Reporting Book traversal links for 6500. OTC BULLETIN BOARD® SERVICE ‹ 6260. Managing Underwriter or Group of Underwriters Obligation To Obtain CUSIP and Provide Notice Up 6510. Applicability ›