=== SEC Form 4 — Statement of Changes in Beneficial Ownership ===
Document Type: 4
Period of Report: 2026-09-21
10b5-1 Pre-arranged Plan: Yes
--- Issuer ---
Name: Datadog, Inc. (DDOG)
CIK: 0001561550
--- Reporting Owner ---
Name: OBSTLER DAVID M
CIK: 0001120741
Role: Officer (Chief Financial Officer)
--- Non-Derivative Transactions ---
[Transaction #1]
Security: Class A Common Stock
Date: 2026-09-21 | Code: S (Open market sale)
Shares: -10,000 | Price: $241.25
Total Value: $2,412,500.00
Shares Owned After: 368,067 | Ownership: D (Direct)
Footnotes:
[F1] Shares sold pursuant to a 10b5-1 plan dated June 13, 2026.
[Transaction #2]
Security: Class A Common Stock
Date: 2026-09-21 | Code: C (Conversion of derivative)
Shares: +3,000 | Price: $0.00
Shares Owned After: 3,000 | Ownership: I (Indirect) | Nature: By Trust
Footnotes:
[F2] Each share of Class B Common Stock is convertible at any time at the option of the Reporting Person into one share of Class A Common Stock and has no expiration date. Each share of Class B Common Stock will convert automatically into one share of Class A Common Stock upon the earliest of: (i) any transfer, whether or not for value, except for certain "Permitted Transfers" as defined in the Issuer's amended and restated certificate of incorporation, (ii) the death of the Reporting Person in the case of shares held directly or in a trustee capacity, and (iii) the tenth anniversary of the Issuer's initial public offering of its Class A Common Stock.
[F3] Shares are held directly by Obstler Children 2019 Trust FBO the Reporting Person's other child, of which the Reporting Person's spouse is Trustee. See Footnote 4.
[Transaction #3]
Security: Class A Common Stock
Date: 2026-09-21 | Code: S (Open market sale)
Shares: -3,000 | Price: $241.25
Total Value: $723,750.00
Shares Owned After: 0 | Ownership: I (Indirect) | Nature: By Trust
Footnotes:
[F1] Shares sold pursuant to a 10b5-1 plan dated June 13, 2026.
[F3] Shares are held directly by Obstler Children 2019 Trust FBO the Reporting Person's other child, of which the Reporting Person's spouse is Trustee. See Footnote 4.
[Transaction #4]
Security: Class A Common Stock
Date: 2026-09-21 | Code: C (Conversion of derivative)
Shares: +3,000 | Price: $0.00
Shares Owned After: 3,000 | Ownership: I (Indirect) | Nature: By Trust
Footnotes:
[F2] Each share of Class B Common Stock is convertible at any time at the option of the Reporting Person into one share of Class A Common Stock and has no expiration date. Each share of Class B Common Stock will convert automatically into one share of Class A Common Stock upon the earliest of: (i) any transfer, whether or not for value, except for certain "Permitted Transfers" as defined in the Issuer's amended and restated certificate of incorporation, (ii) the death of the Reporting Person in the case of shares held directly or in a trustee capacity, and (iii) the tenth anniversary of the Issuer's initial public offering of its Class A Common Stock.
[F4] Shares are held directly by Obstler Children 2019 Trust FBO the Reporting Person's child, of which the Reporting Person's spouse is Trustee. Obstler Children 2019 Trust FBO the Reporting Person's child and Obstler Children 2019 Trust FBO the Reporting Person's other child are separate trusts for the benefit of the Reporting Person's children with substantially identical terms.
[Transaction #5]
Security: Class A Common Stock
Date: 2026-09-21 | Code: S (Open market sale)
Shares: -3,000 | Price: $241.25
Total Value: $723,750.00
Shares Owned After: 0 | Ownership: I (Indirect) | Nature: By Trust
Footnotes:
[F1] Shares sold pursuant to a 10b5-1 plan dated June 13, 2026.
[F4] Shares are held directly by Obstler Children 2019 Trust FBO the Reporting Person's child, of which the Reporting Person's spouse is Trustee. Obstler Children 2019 Trust FBO the Reporting Person's child and Obstler Children 2019 Trust FBO the Reporting Person's other child are separate trusts for the benefit of the Reporting Person's children with substantially identical terms.
--- Derivative Transactions ---
[Transaction #1]
Security: Class B Common Stock
Date: 2026-09-21 | Code: C (Conversion of derivative)
Shares: -3,000 | Price: $0.00
Shares Owned After: 31,198 | Ownership: I (Indirect) | Nature: By Trust
Footnotes:
[F2] Each share of Class B Common Stock is convertible at any time at the option of the Reporting Person into one share of Class A Common Stock and has no expiration date. Each share of Class B Common Stock will convert automatically into one share of Class A Common Stock upon the earliest of: (i) any transfer, whether or not for value, except for certain "Permitted Transfers" as defined in the Issuer's amended and restated certificate of incorporation, (ii) the death of the Reporting Person in the case of shares held directly or in a trustee capacity, and (iii) the tenth anniversary of the Issuer's initial public offering of its Class A Common Stock.
[F2] Each share of Class B Common Stock is convertible at any time at the option of the Reporting Person into one share of Class A Common Stock and has no expiration date. Each share of Class B Common Stock will convert automatically into one share of Class A Common Stock upon the earliest of: (i) any transfer, whether or not for value, except for certain "Permitted Transfers" as defined in the Issuer's amended and restated certificate of incorporation, (ii) the death of the Reporting Person in the case of shares held directly or in a trustee capacity, and (iii) the tenth anniversary of the Issuer's initial public offering of its Class A Common Stock.
[F2] Each share of Class B Common Stock is convertible at any time at the option of the Reporting Person into one share of Class A Common Stock and has no expiration date. Each share of Class B Common Stock will convert automatically into one share of Class A Common Stock upon the earliest of: (i) any transfer, whether or not for value, except for certain "Permitted Transfers" as defined in the Issuer's amended and restated certificate of incorporation, (ii) the death of the Reporting Person in the case of shares held directly or in a trustee capacity, and (iii) the tenth anniversary of the Issuer's initial public offering of its Class A Common Stock.
[F3] Shares are held directly by Obstler Children 2019 Trust FBO the Reporting Person's other child, of which the Reporting Person's spouse is Trustee. See Footnote 4.
[Transaction #2]
Security: Class B Common Stock
Date: 2026-09-21 | Code: C (Conversion of derivative)
Shares: -3,000 | Price: $0.00
Shares Owned After: 31,199 | Ownership: I (Indirect) | Nature: By Trust
Footnotes:
[F2] Each share of Class B Common Stock is convertible at any time at the option of the Reporting Person into one share of Class A Common Stock and has no expiration date. Each share of Class B Common Stock will convert automatically into one share of Class A Common Stock upon the earliest of: (i) any transfer, whether or not for value, except for certain "Permitted Transfers" as defined in the Issuer's amended and restated certificate of incorporation, (ii) the death of the Reporting Person in the case of shares held directly or in a trustee capacity, and (iii) the tenth anniversary of the Issuer's initial public offering of its Class A Common Stock.
[F2] Each share of Class B Common Stock is convertible at any time at the option of the Reporting Person into one share of Class A Common Stock and has no expiration date. Each share of Class B Common Stock will convert automatically into one share of Class A Common Stock upon the earliest of: (i) any transfer, whether or not for value, except for certain "Permitted Transfers" as defined in the Issuer's amended and restated certificate of incorporation, (ii) the death of the Reporting Person in the case of shares held directly or in a trustee capacity, and (iii) the tenth anniversary of the Issuer's initial public offering of its Class A Common Stock.
[F2] Each share of Class B Common Stock is convertible at any time at the option of the Reporting Person into one share of Class A Common Stock and has no expiration date. Each share of Class B Common Stock will convert automatically into one share of Class A Common Stock upon the earliest of: (i) any transfer, whether or not for value, except for certain "Permitted Transfers" as defined in the Issuer's amended and restated certificate of incorporation, (ii) the death of the Reporting Person in the case of shares held directly or in a trustee capacity, and (iii) the tenth anniversary of the Issuer's initial public offering of its Class A Common Stock.
[F4] Shares are held directly by Obstler Children 2019 Trust FBO the Reporting Person's child, of which the Reporting Person's spouse is Trustee. Obstler Children 2019 Trust FBO the Reporting Person's child and Obstler Children 2019 Trust FBO the Reporting Person's other child are separate trusts for the benefit of the Reporting Person's children with substantially identical terms.
--- Holdings ---
[Holding #1]
Security: Class B Common Stock
Ownership: D (Direct)
Footnotes:
[F2] Each share of Class B Common Stock is convertible at any time at the option of the Reporting Person into one share of Class A Common Stock and has no expiration date. Each share of Class B Common Stock will convert automatically into one share of Class A Common Stock upon the earliest of: (i) any transfer, whether or not for value, except for certain "Permitted Transfers" as defined in the Issuer's amended and restated certificate of incorporation, (ii) the death of the Reporting Person in the case of shares held directly or in a trustee capacity, and (iii) the tenth anniversary of the Issuer's initial public offering of its Class A Common Stock.
[F2] Each share of Class B Common Stock is convertible at any time at the option of the Reporting Person into one share of Class A Common Stock and has no expiration date. Each share of Class B Common Stock will convert automatically into one share of Class A Common Stock upon the earliest of: (i) any transfer, whether or not for value, except for certain "Permitted Transfers" as defined in the Issuer's amended and restated certificate of incorporation, (ii) the death of the Reporting Person in the case of shares held directly or in a trustee capacity, and (iii) the tenth anniversary of the Issuer's initial public offering of its Class A Common Stock.
[F2] Each share of Class B Common Stock is convertible at any time at the option of the Reporting Person into one share of Class A Common Stock and has no expiration date. Each share of Class B Common Stock will convert automatically into one share of Class A Common Stock upon the earliest of: (i) any transfer, whether or not for value, except for certain "Permitted Transfers" as defined in the Issuer's amended and restated certificate of incorporation, (ii) the death of the Reporting Person in the case of shares held directly or in a trustee capacity, and (iii) the tenth anniversary of the Issuer's initial public offering of its Class A Common Stock.
--- Footnotes (Complete Index) ---
F1: Shares sold pursuant to a 10b5-1 plan dated June 13, 2026.
F2: Each share of Class B Common Stock is convertible at any time at the option of the Reporting Person into one share of Class A Common Stock and has no expiration date. Each share of Class B Common Stock will convert automatically into one share of Class A Common Stock upon the earliest of: (i) any transfer, whether or not for value, except for certain "Permitted Transfers" as defined in the Issuer's amended and restated certificate of incorporation, (ii) the death of the Reporting Person in the case of shares held directly or in a trustee capacity, and (iii) the tenth anniversary of the Issuer's initial public offering of its Class A Common Stock.
F3: Shares are held directly by Obstler Children 2019 Trust FBO the Reporting Person's other child, of which the Reporting Person's spouse is Trustee. See Footnote 4.
F4: Shares are held directly by Obstler Children 2019 Trust FBO the Reporting Person's child, of which the Reporting Person's spouse is Trustee. Obstler Children 2019 Trust FBO the Reporting Person's child and Obstler Children 2019 Trust FBO the Reporting Person's other child are separate trusts for the benefit of the Reporting Person's children with substantially identical terms.
--- Signature ---
/s/ /s/ Kerry Acocella, Attorney-in-Fact (2026-09-23)
