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<cov:edgarSubmission xmlns:cov="http://www.sec.gov/edgar/atsn/cover" xmlns:ats="http://www.sec.gov/edgar/atsncommon">
  <cov:submissionType>ATS-N/MA</cov:submissionType>
  <cov:rbOperatesPursuantToFormATS>N</cov:rbOperatesPursuantToFormATS>
  <cov:accessionNumber>0000310607-23-000020</cov:accessionNumber>
  <cov:filerCredentials>
    <cov:filerCik>0000310607</cov:filerCik>
    <cov:filerCcc>XXXXXXXX</cov:filerCcc>
  </cov:filerCredentials>
  <cov:fileNumber>013-00105</cov:fileNumber>
  <cov:txNMSStockATSName>CBX</cov:txNMSStockATSName>
  <cov:taStatementAboutAmendment>Part II Item 7(b) and 15 and Part III Item 15 are amended to introduce a real-time continuous data feed from the CBX Main System to the Broker-Dealer Operator Smart Order Router technology. The changes herein apply to the Broker-Dealer Operator (which operates the SOR) and Subscribers that access the CBX via the SOR.</cov:taStatementAboutAmendment>
  <cov:liveTestFlag>LIVE</cov:liveTestFlag>
  <cov:flags>
    <cov:overrideInternetFlag>false</cov:overrideInternetFlag>
    <cov:confirmingCopyFlag>false</cov:confirmingCopyFlag>
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