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  <cov:submissionType>ATS-N/MA</cov:submissionType>
  <cov:rbOperatesPursuantToFormATS>N</cov:rbOperatesPursuantToFormATS>
  <cov:accessionNumber>0001193125-25-317336</cov:accessionNumber>
  <cov:filerCredentials>
    <cov:filerCik>0000042352</cov:filerCik>
    <cov:filerCcc>XXXXXXXX</cov:filerCcc>
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  <cov:fileNumber>013-00121</cov:fileNumber>
  <cov:txNMSStockATSName>Sigma X2</cov:txNMSStockATSName>
  <cov:taStatementAboutAmendment>This Material Amendment revises Part III, Items 13.a. and 13.d. to describe Participant Categories, a type of segmentation within Sigma X2's Counterparty Classification Framework by which each Direct Subscriber MPID or GSID, as applicable, will be designated as either Participant Category 1 or Participant Category 2. Except with respect to directed orders to Sigma X2 via SOR, such categorization may be used by GSCO Algorithms and SOR, on behalf of Indirect Subscribers, to determine the Participant Category/Categories with which such orders may interact on an order-by-order basis. Related and conforming revisions are also made to Part II Item 7.d, Part III, Items 3.a., 9.a., 11.a., 11.c., 14.a., and 14.b. and, separately, Part III, Item 13.a. is revised to reflect GSCO's ability to change a Participant's assigned Liquidity Taker Category on an intra-month basis if, following a category change, the Participant's behavior materially changes in a manner that is no longer consistent with the recently assigned category. As described, the revisions pertain to Sigma X2 Subscribers including GSCO, the broker-dealer operator of Sigma X2.</cov:taStatementAboutAmendment>
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