Sean William Ostrower - 28 Sep 2026 Form 4 Insider Report for Avalanche Treasury Corp (AVAT)

Reporting relationship: Chief Financial Officer
Issuer ticker: AVAT
Reported as of: 28 Sep 2026
Net transaction value: $0
SEC form: 4
Accepted by SEC: 30 Sep 2026, 18:33:27 UTC
Prior SEC filing: 11 Jun 2026
Source filing: View source filing
Reporting owner signature: /s/ Laine Mihalchick Moljo, as Attorney-in-Fact

Key filing fact

Sean William Ostrower filed Form 4 for Avalanche Treasury Corp (AVAT) on 30 Sep 2026.

Key facts

This page summarizes Sean William Ostrower's Form 4 filing for Avalanche Treasury Corp (AVAT).
2 reported transactions and 0 derivative rows are listed below.
Accepted by SEC: 30 Sep 2026, 18:33.

Change

Previous filing in this sequence was filed on 11 Jun 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

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0002125266 Primary reporting owner

Ostrower Sean William

Relationship: Chief Financial Officer
Address: AVALANCHE TREASURY COMPANY, LLC., 11 W. 42ND STREET, 2ND FLOOR, NEW YORK
Signature: /s/ Laine Mihalchick Moljo, as Attorney-in-Fact
Signature date: 30 Sep 2026

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

AVAT transaction

Class A Common Stock

Award

Transaction value
Shares: +299,401
Change %
Price: $0.000000^*
Shares after: 299,401
Date: 28 Sep 2026
Ownership: Direct
Footnotes: F1

AVAT transaction

Class A Common Stock

Tax liability

Transaction value
Shares: -15,541
Change %: -5.2%
Price: $1.90^*
Shares after: 283,860
Date: 30 Sep 2026
Ownership: Direct
Footnotes: F2

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 2 footnotes

Footnote F1

Represents a grant of restricted stock units ("RSUs") on September 28, 2026. The RSUs will vest 1/8 on each of the first eight six-month anniversaries of March 9, 2026. Each RSU represents a contingent right to receive one share of Class A common stock.

Footnote F2

Represents shares of Class A Common Stock withheld by the Issuer to satisfy tax withholding upon the vesting of RSUs.