STOCK TITAN

[Form 4] Nuburu, Inc. Insider Trading Activity

Filing Impact
(Very High)
Filing Sentiment
(Positive)
Form Type
4

Rhea-AI Filing Summary

Nuburu, Inc. director and Co‑Chief Executive Officer Alessandro Zamboni reported two acquisitions of common stock. On December 31, 2025, Vanguard Holdings S.r.l., an entity owned by him, recorded an open‑market purchase of 4,332,525 shares at $0.3453 per share, held indirectly. A footnote explains this reflects the conversion of two Company convertible promissory notes of $545,000 and $900,000, plus interest, into 21,619,298 shares before adjustment for a 1‑for‑4.99 reverse stock split.

Separately, on October 1, 2025, Zamboni was granted 1,774,000 restricted stock units, which vested on October 31, 2025. After the 2026 reverse stock split, this grant is shown in the table as 355,511 shares of common stock held directly.

Positive

  • None.

Negative

  • None.
Insider Zamboni Alessandro
Role Co-Chief Executive Officer
Bought 4,332,525 shs ($1.50M)
Type Security Shares Price Value
Purchase Common Stock 4,332,525 $0.3453 $1.50M
Grant/Award Common Stock 355,511 $0.00 --
Holdings After Transaction: Common Stock — 4,332,525 shares (Indirect, By Vanguard Holdings S.r.l.); Common Stock — 355,511 shares (Direct, null)
Footnotes (1)
  1. On October 1, 2025, the reporting person was granted 1,774,000 restricted stock units, which vested on October 31, 2025. Nuburu, Inc. (the "Company") effected a reverse stock split on February 27, 2026, and its common stock began trading on a 1-for-4.99 split-adjusted basis (with every 4.99 shares being converted into a single share) at the commencement of trading on March 2, 2026 (the "2026 Reverse Stock Split"). The number of restricted stock units in the table has been adjusted for the 2026 Reverse Stock Split. On December 31, 2025, Vanguard Holdings S.r.l., an entity owned by the reporting person, converted (i) a convertible promissory note in the amount of $545,000 issued by Nuburu, Inc. (the "Company"), plus outstanding interest, and (ii) a convertible promissory note in the amount of $900,000 issued by the Company, plus outstanding interest, in exchange for 21,619,298 shares of common stock at a conversion price equal to a 33.33% discount to the lowest daily volume weighted average price as reported by Bloomberg L.P. during the five days prior to the conversion date. The number of shares acquired and the price per share in the table have been adjusted for the 2026 Reverse Stock Split.
Common shares acquired (indirect) 4,332,525 shares Open-market purchase reported for December 31, 2025
Purchase price per share $0.3453 per share Price for 4,332,525 Nuburu common shares
RSUs originally granted 1,774,000 restricted stock units Grant on October 1, 2025, vested October 31, 2025
RSUs after reverse split 355,511 shares Split-adjusted RSU amount shown in ownership table
First convertible note principal $545,000 Convertible promissory note converted into common stock
Second convertible note principal $900,000 Additional convertible promissory note converted into stock
Shares from note conversion (pre-split) 21,619,298 shares Shares issued upon conversion before 1-for-4.99 reverse split
Conversion discount to VWAP 33.33% discount Discount to lowest five-day volume weighted average price
restricted stock units financial
"the reporting person was granted 1,774,000 restricted stock units, which vested on October 31, 2025"
Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.
reverse stock split financial
"the Company effected a reverse stock split on February 27, 2026, and its common stock began trading on a 1-for-4.99 split-adjusted basis"
A reverse stock split is when a company reduces the number of its shares outstanding, making each share more valuable. For example, if you own 100 shares worth $1 each, a 1-for-10 reverse split would turn your 100 shares into 10 shares worth $10 each. Companies often do this to boost their stock price and appear more stable to investors.
convertible promissory note financial
"converted (i) a convertible promissory note in the amount of $545,000 issued by Nuburu, Inc., plus outstanding interest"
A convertible promissory note is a loan a company takes now that can later be turned into shares instead of being repaid in cash. Think of it as lending money with the option to accept ownership in the business down the road; that matters to investors because it affects who gets paid first, how much ownership existing shareholders keep, and the company’s future valuation and cash needs. Terms such as conversion price, interest and maturity determine the financial impact.
volume weighted average price financial
"at a conversion price equal to a 33.33% discount to the lowest daily volume weighted average price"
The volume weighted average price (VWAP) is a way to measure the average price of a security, such as a stock, over a specific period, taking into account how many units were traded at each price. It’s similar to calculating the average cost of items bought when some are more frequently purchased than others. Investors use VWAP to assess whether a security is being bought or sold at a fair price during trading.
split-adjusted basis financial
"its common stock began trading on a 1-for-4.99 split-adjusted basis at the commencement of trading"
An adjustment to historical share prices and share counts that reflects past stock splits or reverse splits so that old data lines up with the current number of shares. Think of it like resizing an old photograph so it matches a new frame: it keeps price charts, returns and per‑share metrics comparable over time, which matters to investors who need accurate performance, valuation and trend analysis.
SEC Form 4
FORM 4UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940
OMB APPROVAL
OMB Number:3235-0287
Estimated average burden
hours per response:0.5
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.
1. Name and Address of Reporting Person*
Zamboni Alessandro

(Last)(First)(Middle)
C/O NUBURU, INC.
44 COOK STREET, SUITE 100

(Street)
DENVER COLORADO 80206

(City)(State)(Zip)

UNITED STATES

(Country)
2. Issuer Name and Ticker or Trading Symbol
Nuburu, Inc. [ BURU ]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
XDirector10% Owner
XOfficer (give title below)Other (specify below)
Co-Chief Executive Officer
2a. Foreign Trading Symbol
3. Date of Earliest Transaction (Month/Day/Year)
10/01/2025
6. Individual or Joint/Group Filing (Check Applicable Line)
XForm filed by One Reporting Person
Form filed by More than One Reporting Person
4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year)2A. Deemed Execution Date, if any (Month/Day/Year)3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4)
CodeVAmount(A) or (D)Price
Common Stock10/01/2025A355,511(1)A$0355,511D
Common Stock12/31/2025P4,332,525(2)A$0.3453(2)4,332,525IBy Vanguard Holdings S.r.l.
Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year)3A. Deemed Execution Date, if any (Month/Day/Year)4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 6. Date Exercisable and Expiration Date (Month/Day/Year)7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4)
CodeV(A)(D)Date ExercisableExpiration DateTitleAmount or Number of Shares
Explanation of Responses:
1. On October 1, 2025, the reporting person was granted 1,774,000 restricted stock units, which vested on October 31, 2025. Nuburu, Inc. (the "Company") effected a reverse stock split on February 27, 2026, and its common stock began trading on a 1-for-4.99 split-adjusted basis (with every 4.99 shares being converted into a single share) at the commencement of trading on March 2, 2026 (the "2026 Reverse Stock Split"). The number of restricted stock units in the table has been adjusted for the 2026 Reverse Stock Split.
2. On December 31, 2025, Vanguard Holdings S.r.l., an entity owned by the reporting person, converted (i) a convertible promissory note in the amount of $545,000 issued by Nuburu, Inc. (the "Company"), plus outstanding interest, and (ii) a convertible promissory note in the amount of $900,000 issued by the Company, plus outstanding interest, in exchange for 21,619,298 shares of common stock at a conversion price equal to a 33.33% discount to the lowest daily volume weighted average price as reported by Bloomberg L.P. during the five days prior to the conversion date. The number of shares acquired and the price per share in the table have been adjusted for the 2026 Reverse Stock Split.
/s/ Alessandro Zamboni04/22/2026
** Signature of Reporting PersonDate
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)

FAQ

What insider share purchase did Nuburu (BURU) report for Alessandro Zamboni?

Nuburu reported that Vanguard Holdings S.r.l., an entity owned by Co‑CEO Alessandro Zamboni, acquired 4,332,525 shares of common stock at $0.3453 per share on December 31, 2025, held as an indirect ownership position.

How were Nuburu (BURU) convertible notes converted into shares for Vanguard Holdings S.r.l.?

According to the filing, Vanguard Holdings S.r.l. converted two Nuburu convertible promissory notes of $545,000 and $900,000, plus interest, into 21,619,298 shares of common stock at a 33.33% discount to the lowest five‑day volume weighted average price.

What restricted stock unit grant did Nuburu (BURU) give Alessandro Zamboni?

On October 1, 2025, Nuburu granted Alessandro Zamboni 1,774,000 restricted stock units, which fully vested on October 31, 2025. After a 1‑for‑4.99 reverse stock split, this award appears as 355,511 common shares in the ownership table.

How did Nuburu’s 2026 reverse stock split affect Alessandro Zamboni’s equity awards?

Nuburu implemented a 1‑for‑4.99 reverse stock split, with trading beginning on a split‑adjusted basis on March 2, 2026. Both the restricted stock units and the share amounts from the note conversion were adjusted to reflect this split ratio.

Is Alessandro Zamboni’s 4.33M-share Nuburu (BURU) position held directly or indirectly?

The 4,332,525 shares linked to the December 31, 2025 transaction are reported as held indirectly through Vanguard Holdings S.r.l., an entity owned by Alessandro Zamboni. The 355,511 shares from vested restricted stock units are held directly.