Yes. Firms required to synchronize their clocks according to the CAT NMS Plan should keep a log of the times when they synchronize their clocks and the results of the synchronization process. This log should include notice of any time the clock drifts more than allowed by the CAT NMS Plan. Logs must be maintained consistent with the five-year retention period in paragraph (b) of the Participants’ common clock synchronization rule and accessible to the firm or made available by the firm in response to a regulatory request on a reasonably prompt basis whether maintained and preserved on site or by a third party.