Key facts
- This page summarizes MAINSAIL GP III, LLC's Form 4 filing for Brilliant Earth Group, Inc. (BRLT).
- 2 reported transactions and 5 derivative rows are listed below.
- Accepted by SEC: 26 Aug 2026, 16:15.
MAINSAIL GP III, LLC - 24 Aug 2026 Form 4 Insider Report for Brilliant Earth Group, Inc. (BRLT)
- Reporting relationship
- 10%+ Owner
- Issuer ticker
- BRLT
- Reported as of
- 24 Aug 2026
- Net transaction value
- $0
- SEC form
- 4
- Accepted by SEC
- 26 Aug 2026, 16:15:04 UTC
- Prior SEC filing
- 12 Aug 2026
- Source filing
- View source filing
- Reporting owner signature
- /s/ Gavin Turner, Mainsail GP III, LLC
Source evidence
Original filing metadata and source links for verification.
4 source fields
Reporting owner
1 detail
Key filing fact
MAINSAIL GP III, LLC filed Form 4 for Brilliant Earth Group, Inc. (BRLT) on 26 Aug 2026.
Change
- Previous filing in this sequence was filed on 12 Aug 2026.
- Current net transaction value: $0.
Research use
- This tells you what this filing adds before you inspect full transaction and derivative tables.
- You can trace every row back to the original SEC filing document.
Evidence
Filed on Form 4
View source filing
Ownership activity is grounded in SEC Form 4 disclosures.
Reporting Owners (5)
CIK 0001883360
Primary reporting owner
MAINSAIL GP III, LLC
- Relationship
- 10%+ Owner
- Address
- C/O MAINSAIL MANAGEMENT COMPANY, LLC, 500 WEST 5TH STREET, SUITE 1100, AUSTIN
- Signature
- /s/ Gavin Turner, Mainsail GP III, LLC
- Signature date
- 26 Aug 2026
CIK 0001543760
Mainsail Partners III, L.P.
- Relationship
- 10%+ Owner
- Address
- C/O MAINSAIL MANAGEMENT COMPANY, LLC, 500 WEST 5TH STREET, SUITE 1100, AUSTIN
- Signature
- /s/ Gavin Turner, Mainsail Partners III, L.P.
- Signature date
- 26 Aug 2026
CIK 0001570211
Mainsail Co-Investors III, L.P.
- Relationship
- 10%+ Owner
- Address
- C/O MAINSAIL MANAGEMENT COMPANY, LLC, 500 WEST 5TH STREET, SUITE 1100, AUSTIN
- Signature
- /s/ Gavin Turner, Mainsail Co-Investors III, L.P.
- Signature date
- 26 Aug 2026
CIK 0001883293
MAINSAIL INCENTIVE PROGRAM, LLC
- Relationship
- 10%+ Owner
- Address
- C/O MAINSAIL MANAGEMENT COMPANY, LLC, 500 WEST 5TH STREET, SUITE 1100, AUSTIN
- Signature
- /s/ Gavin Turner, Mainsail Incentive Program, LLC
- Signature date
- 26 Aug 2026
CIK 0001883367
MAINSAIL MANAGEMENT COMPANY, LLC
- Relationship
- 10%+ Owner
- Address
- C/O MAINSAIL MANAGEMENT COMPANY, LLC, 500 WEST 5TH STREET, SUITE 1100, AUSTIN
- Signature
- /s/ Gavin Turner, Mainsail Management Company, LLC
- Signature date
- 26 Aug 2026
Reported non-derivative transactions
Shares, units, or other non-derivative securities reported in this filing.
BRLT
transaction
Class B Common Stock
Other
- Transaction value
- Shares
- +16,014
- Change %
- +0.05%
- Price
- Shares after
- 31,848,071
- Date
- 24 Aug 2026
- Ownership
- See footnotes
- Footnotes
- F1, F2, F3
BRLT
transaction
Class B Common Stock
Other
- Transaction value
- Shares
- +16,014
- Change %
- +0.05%
- Price
- Shares after
- 31,848,071
- Date
- 24 Aug 2026
- Ownership
- See footnotes
- Footnotes
- F1, F2, F3
BRLT
transaction
Class B Common Stock
Other
- Transaction value
- Shares
- +16,014
- Change %
- +0.05%
- Price
- Shares after
- 31,848,071
- Date
- 24 Aug 2026
- Ownership
- See footnotes
- Footnotes
- F1, F2, F3
BRLT
transaction
Class B Common Stock
Other
- Transaction value
- Shares
- +16,014
- Change %
- +0.05%
- Price
- Shares after
- 31,848,071
- Date
- 24 Aug 2026
- Ownership
- See footnotes
- Footnotes
- F1, F2, F3
BRLT
transaction
Class B Common Stock
Other
- Transaction value
- Shares
- +16,014
- Change %
- +0.05%
- Price
- Shares after
- 31,848,071
- Date
- 24 Aug 2026
- Ownership
- See footnotes
- Footnotes
- F1, F2, F3
Reported derivative securities
Options, warrants, convertible securities, or similar derivative positions disclosed in the filing.
BRLT
transaction
Derivative
LLC Units
Other
- Transaction value
- Shares
- +16,014
- Change %
- +0.05%
- Price
- Shares after
- 31,848,071
- Date
- 24 Aug 2026
- Ownership
- See footnotes
- Underlying class
- Class A Common Stock
- Underlying amount
- 16,014
- Exercise price
- Footnotes
- F1, F2, F3, F4
BRLT
transaction
Derivative
LLC Units
Other
- Transaction value
- Shares
- +16,014
- Change %
- +0.05%
- Price
- Shares after
- 31,848,071
- Date
- 24 Aug 2026
- Ownership
- See footnotes
- Underlying class
- Class A Common Stock
- Underlying amount
- 16,014
- Exercise price
- Footnotes
- F1, F2, F3, F4
BRLT
transaction
Derivative
LLC Units
Other
- Transaction value
- Shares
- +16,014
- Change %
- +0.05%
- Price
- Shares after
- 31,848,071
- Date
- 24 Aug 2026
- Ownership
- See footnotes
- Underlying class
- Class A Common Stock
- Underlying amount
- 16,014
- Exercise price
- Footnotes
- F1, F2, F3, F4
BRLT
transaction
Derivative
LLC Units
Other
- Transaction value
- Shares
- +16,014
- Change %
- +0.05%
- Price
- Shares after
- 31,848,071
- Date
- 24 Aug 2026
- Ownership
- See footnotes
- Underlying class
- Class A Common Stock
- Underlying amount
- 16,014
- Exercise price
- Footnotes
- F1, F2, F3, F4
BRLT
transaction
Derivative
LLC Units
Other
- Transaction value
- Shares
- +16,014
- Change %
- +0.05%
- Price
- Shares after
- 31,848,071
- Date
- 24 Aug 2026
- Ownership
- See footnotes
- Underlying class
- Class A Common Stock
- Underlying amount
- 16,014
- Exercise price
- Footnotes
- F1, F2, F3, F4
* marks a reported price that did not pass the local price check.
Additional SEC filing notes
Filing notes and footnotes
Explanation of responses 4 footnotes
Footnote F1
The reported transaction, which involves a purchase of a limited partner's interest in Mainsail Co-Investors III, L.P. ("MCOI"), may represent a change in the Reporting Persons' pecuniary interest in common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock held by MCOI. For purposes of Section 16(b), such deemed purchase, for an aggregate consideration of $18,096, could be matchable against the sales reported on August 10, 2026, as reported on the Form 4 filed by the Reporting Persons on August 12, 2026. Accordingly, the Reporting Persons have fully disgorged to the Issuer, the Section 16(b) deemed profit of $2,033.
Footnote F2
Consists of (i) 31,098,704 shares of Class B common stock (and associated LLC Units) held by Mainsail Partners III, L.P. ("MP III"), (ii) 61,823 shares of Class B common stock (and associated LLC Units) held by Mainsail Incentive Program, LLC ("MIP"), and (iii) 687,544 shares of Class B common stock (and associated LLC Units) held by MCOI.
Footnote F3
Mainsail GP III, LLC ("GP III") is the general partner of MP III. MCOI is a co-investment vehicle that invests alongside MP III. GP III is the general partner of MCOI. A three member investment committee of GP III acts by a majority vote, with Gavin Turner possessing a veto right, with respect to the voting and dispositive power of the securities held by MP III and MCOI. Mainsail Management Company, LLC ("MMC") is the managing member of MIP, and Gavin Turner is the sole Manager of MMC. Mr. Turner has separately reported the transactions and reported securities reflected in this statement. The Reporting Persons disclaim beneficial ownership of the reported securities except to the extent of their respective pecuniary interests therein.
Footnote F4
LLC Units (together with one share of Class B common stock for every LLC Unit) are exchangeable for one share of the Issuer's Class A common stock. The reported LLC Units, which were acquired by the Reporting Persons prior to the Issuer's initial public offering, do not expire.