Form 8-K VICOR CORP For: Sep 09

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): September 9, 2026

VICOR CORPORATION

(Exact Name of Registrant as Specified in its Charter)

25 Frontage Road, Andover, Massachusetts 01810

(Address of Principal Executive Offices) (Zip Code)

(978) 470-2900

(Registrant’s telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 or Rule 12b-2 of the Securities Exchange Act of 1934.

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 5.03. Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year

Effective September 9, 2026, the Board of Directors of Vicor Corporation (“Vicor”) amended Vicor’s By-laws to clarify provisions relating to the removal of directors in Article II, Section 6 thereof. The foregoing summary is qualified in its entirety by reference to the full text of the amended By-laws, which are attached hereto as Exhibit 3.1 (unmarked version) and Exhibit 3.2 (marked version), and are incorporated by reference herein.

Item 9.01. Financial Statements and Exhibits

(d) Exhibits

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.