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  <noticeSignature>
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text: 144
  0001654074
  XXXXXXXX
  LIVE
  0001835830
  Klaviyo, Inc.
  001-41806
  125 Summer Street, 6th Floor
  Boston
  MA
  02110
  617-213-1788
  SUMMIT INVESTORS GE IX/VC IV, LLC
  Owner
  Series A common stock, par value $0.001 per share
  Barclays Capital Inc.
  745 7th Avenue
  New York
  NY
  10019
  10872
  401720.4
  78803963
  11/14/2024
  NYSE
  Series A common stock, par value $0.001 per share
  09/20/2023
  Pre-IPO transactions.
  Klaviyo, Inc.
  N
  169076
  09/20/2023
  Equity interests in the Issuer were purchased pre-IPO.
  N
  Summit Investors GE IX/VC IV, LLC
  222 Berkeley St 18th FL
  Boston
  MA
  02116
  Series A common stock, par value $0.001 per share
  08/16/2024
  753
  23929.8
  Summit Investors GE IX/VC IV, LLC
  222 Berkeley St 18th FL
  Boston
  MA
  02116
  Series A common stock, par value $0.001 per share
  08/20/2024
  422
  13481
  Summit Investors GE IX/VC IV, LLC
  222 Berkeley St 18th FL
  Boston
  MA
  02116
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  11243.15
  Summit Investors GE IX/VC IV, LLC
  222 Berkeley St 18th FL
  Boston
  MA
  02116
  Series A common stock, par value $0.001 per share
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  256
  8131.22
  Summit Investors GE IX/VC IV, LLC
  222 Berkeley St 18th FL
  Boston
  MA
  02116
  Series A common stock, par value $0.001 per share
  08/23/2024
  949
  30684.69
  Summit Investors GE IX/VC IV, LLC
  222 Berkeley St 18th FL
  Boston
  MA
  02116
  Series A common stock, par value $0.001 per share
  08/26/2024
  281
  9067.57
  Summit Investors GE IX/VC IV, LLC
  222 Berkeley St 18th FL
  Boston
  MA
  02116
  Series A common stock, par value $0.001 per share
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  209
  6749.45
  Summit Investors GE IX/VC IV, LLC
  222 Berkeley St 18th FL
  Boston
  MA
  02116
  Series A common stock, par value $0.001 per share
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  85
  2692.53
  Summit Investors GE IX/VC IV, LLC
  222 Berkeley St 18th FL
  Boston
  MA
  02116
  Series A common stock, par value $0.001 per share
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  53
  1671.94
  Summit Investors GE IX/VC IV, LLC
  222 Berkeley St 18th FL
  Boston
  MA
  02116
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  4
  126.56
  Summit Investors GE IX/VC IV, LLC
  222 Berkeley St 18th FL
  Boston
  MA
  02116
  Series A common stock, par value $0.001 per share
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  19
  599.03
  Summit Investors GE IX/VC IV, LLC
  222 Berkeley St 18th FL
  Boston
  MA
  02116
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  9
  279.09
  Summit Investors GE IX/VC IV, LLC
  222 Berkeley St 18th FL
  Boston
  MA
  02116
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  Summit Investors GE IX/VC IV, LLC
  222 Berkeley St 18th FL
  Boston
  MA
  02116
  Series A common stock, par value $0.001 per share
  09/13/2024
  353
  11109.45
  11/14/2024
  /s/ Adam Hennessey