ImageneBio (IMA) prospectus supplement registers 2.5M shares for resale

Rhea-AI Filing Summary

ImageneBio, Inc. filed a prospectus supplement to its Form S-1 registering the resale or other disposition of 2,508,337 shares of Common Stock. The supplement incorporates portions of a Form 8-K noting that Senior VP of Finance and Operations Robert Lally gave notice of resignation, effective July 22, 2026. The supplement states the last reported sales price was $6.02 per share on June 26, 2026 and that the selling stockholders, identified in the prospectus, propose to offer those shares from time to time.

Insights

Equity Capital Markets Analyst

Resale registration creates potential share supply; immediate dilution depends on selling activity.

The prospectus supplement registers 2,508,337 shares for resale by selling stockholders under the S-1 registration. The filing is a resale registration, not a primary issuance; the company states these are offered for resale by holders.

Cash treatment is described as proceeds flowing to selling holders rather than the issuer; timing and pace of resales depend on holder decisions and distribution methods stated in the prospectus.

Corporate Governance / HR Advisor

Finance leadership change announced; replacement search is planned.

The Form 8-K excerpt states that Robert Lally, Senior VP of Finance and Operations and principal accounting officer, gave notice of resignation effective July 22, 2026. The company says the resignation was not due to any disagreement and that it will search for a replacement.

Leadership transitions can affect finance operations during the interim; subsequent filings may disclose an interim appointee or transition arrangements.

Key Figures

Shares registered for resale: 2,508,337 shares Last reported sales price: $6.02 per share Resignation effective date: July 22, 2026

3 metrics

Shares registered for resale 2,508,337 shares Prospectus supplement to S-1

Last reported sales price $6.02 per share June 26, 2026

Resignation effective date July 22, 2026 Senior VP Finance and Operations Robert Lally

Key Terms

prospectus supplement, selling stockholders, resale registration

3 terms

prospectus supplement regulatory

"This prospectus supplement supplements the prospectus dated April 2, 2026"

A prospectus supplement is an additional document provided alongside a company's main offering details, offering updated or extra information about a specific financial product being sold. It helps investors understand the latest terms, risks, and details of the investment, similar to how an update or revision clarifies or expands on original instructions, ensuring they have current and complete information before making a decision.

selling stockholders financial

"resale or other disposition from time to time by the selling stockholders identified in this prospectus"

Selling stockholders are existing owners of a company's shares who are offering some or all of their holdings for sale, often as part of a public offering or secondary transaction. For investors this matters because such sales increase the number of shares available to buy, can signal how confident current owners are about future prospects, and may put short-term pressure on the stock price similar to more tickets being released for a popular event.

resale registration regulatory

"the proposed offer and resale or other disposition from time to time by the selling stockholders"

Resale registration is the formal filing with securities regulators that allows previously restricted or privately held shares to be sold publicly. Think of it as getting official permission to unlock and list a sealed package of stock so it can be traded openly; that matters to investors because it increases liquidity, can change the number of shares available on the market, and reduces legal risk for sellers, all of which can affect a company’s share price.

Offering Details

resale

Offering

Offering Type resale

Use of Proceeds Proceeds from sales are to be received by the selling stockholders, not the issuer

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 06/29/2026 - 07:08 AM Accepted by SEC EDGAR 06/29/2026 - 07:05 AM Learn about SEC filing dates

FAQ

What does the ImageneBio (IMA) prospectus supplement register?

It registers the resale or other disposition of 2,508,337 shares of Common Stock by the selling stockholders. The supplement updates the S-1 prospectus and incorporates portions of the Form 8-K filed June 26, 2026.

Will ImageneBio receive proceeds from sales of the registered shares?

The offering is a resale by selling stockholders; proceeds go to those holders. The prospectus describes resale by holders rather than a primary issuance by the company.

What price was ImageneBio's stock trading at when the supplement was filed?

The supplement states the last reported sales price was $6.02 per share on June 26, 2026. That price is provided as a market reference in the prospectus supplement.

Did ImageneBio disclose any management changes in this filing?

Yes. The Form 8-K excerpt states Robert Lally, Senior VP of Finance and Operations and principal accounting officer, gave notice of resignation effective July 22, 2026, and the company plans to search for a replacement.

How can the registered resale affect IMA's share supply?

Registration permits selling holders to offer up to 2,508,337 shares over time; actual market impact depends on the timing and method of individual sales, which are determined by the selling holders.

Filed Pursuant to Rule 424(b)(3)
Registration No. 333-290108

PROSPECTUS SUPPLEMENT

(To Prospectus dated April 2, 2026)

ImageneBio, Inc.

2,508,337 Shares of Common Stock

This prospectus supplement supplements the prospectus dated April 2, 2026 (the “Prospectus”), which forms a part of our registration statement on Form S-1 (No. 333-290108), as amended. This prospectus supplement is being filed to update and supplement the information in the Prospectus with certain information contained in our Current Report on Form 8-K, filed with the Securities and Exchange Commission on June 26, 2026 (the “Current Report”). Accordingly, we have attached the Current Report in relevant part to this prospectus supplement.

The Prospectus and this prospectus supplement relate to the proposed offer and resale or other disposition from time to time by the selling stockholders identified in this prospectus of 2,508,337 shares of common stock, par value $0.001 per share, (the “Common Stock”) of ImageneBio, Inc.

Our Common Stock is listed on the Nasdaq Capital Market under the ticker symbol “IMA.” On June 26, 2026, the last reported sales price of our Common Stock was $6.02 per share.

This prospectus supplement should be read in conjunction with the Prospectus, including any amendments or supplements to it, which is to be delivered with this prospectus supplement. This prospectus supplement is qualified by reference to the Prospectus, including any amendments or supplements thereto, except to the extent that the information provided by this prospectus supplement supersedes information contained in the Prospectus.

This prospectus supplement is not complete without, and may not be delivered or used except in conjunction with, the Prospectus, including any amendments or supplements to it.

Investing in our securities involves a high degree of risk. You should review carefully the risks and uncertainties described in the section titled “Risk Factors” beginning on page 6 of the Prospectus, and under similar headings in any amendments or supplements to the Prospectus.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities, or passed upon the accuracy or adequacy of this prospectus supplement. Any representation to the contrary is a criminal offense.

The date of this prospectus supplement is June 29, 2026

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): June 22, 2026

IMAGENEBIO, INC.

(Exact name of registrant as specified in its charter)

Delaware		001-40287		81-1697316
(State or other jurisdiction of incorporation)		(Commission File Number)		(I.R.S. Employer Identification No.)

12526 High Bluff Drive, Suite 345
San Diego, California		92130
(Address of principal executive offices)		(Zip Code)

Registrant’s telephone number, including area code: (858) 345-6265

Not Applicable

(Former Name or Former Address, if Changed Since Last Report)

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:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

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

Title of each class		Trading Symbol(s)		Name of each exchange on which registered
Common Stock, $0.001 par value		IMA		The Nasdaq Capital Market

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

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 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

On June 22, 2026, Robert Lally, our Senior Vice President of Finance and Operations and principal accounting officer, provided notice of his resignation, effective July 22, 2026. Mr. Lally’s resignation was not due to any disagreement with the Company. We plan to conduct a search for Mr. Lally’s replacement.

SIGNATURE

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.

				IMAGENEBIO, INC.
Date: June 26, 2026				By:		/s/ Kristin Yarema
						Kristin Yarema, Ph.D.
						Chief Executive Officer