MBX Biosciences (MBX) sells 2.25M shares to raise $87.1M via ATM

Rhea-AI Filing Summary

MBX Biosciences, Inc. closed an at-the-market stock sale, issuing 2,250,986 shares of common stock at a volume weighted average price of $38.76 per share for gross proceeds of approximately $87.1 million. The shares were sold through Jefferies under an existing Open Market Sale Agreement and shelf registration on Form S-3.

The company currently plans to use the net proceeds to fund clinical-stage programs, discovery research and development, additional clinical development, and general corporate purposes including working capital and capital expenditures. MBX Biosciences may also use some proceeds and existing cash to in-license, acquire, or invest in complementary businesses or technologies, and still has capacity to sell up to an additional $62.9 million of common stock under the same program.

Insights

Biotech capital markets analyst

MBX raises $87.1M via ATM, boosting cash for R&D while allowing more issuance.

MBX Biosciences completed an at-the-market equity sale of 2,250,986 common shares at $38.76, generating gross proceeds of about $87.1 million. This is a direct primary capital raise, using an existing shelf registration and Open Market Sale Agreement with Jefferies.

The company states it intends to direct net proceeds to clinical-stage programs, discovery research and development, additional clinical development, and general corporate purposes such as working capital and capital expenditures. It also leaves open potential use for in-licensing or acquisitions of complementary assets.

After this transaction, MBX can still offer and sell up to an additional $62.9 million of common stock through Jefferies under the same at-the-market program. Actual dilution and capital inflows from future sales will depend on if and when MBX chooses to utilize this remaining capacity.

false000177611100017761112026-02-042026-02-04

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): February 04, 2026

MBX Biosciences, Inc.

(Exact name of Registrant as Specified in Its Charter)

Delaware			001-42272	84-1882872
(State or Other Jurisdiction of Incorporation)			(Commission File Number)	(IRS Employer Identification No.)
11711 N. Meridian Street Suite 300
Carmel, Indiana				46032
(Address of Principal Executive Offices)				(Zip Code)

Registrant’s Telephone Number, Including Area Code: (317) 659-0200

(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, $0.0001 par value per share		MBX		Nasdaq Global Select 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 8.01 Other Events.

Sales Pursuant to At-the-Market ("ATM") Offering Program

On February 4, 2026, MBX Biosciences, Inc. (the “Company”), closed on the sale and issuance of an aggregate of 2,250,986 shares of its common stock (the "Shares") at a volume weighted average price per share of $38.76 for gross proceeds of approximately $87.1 million. The Shares were sold pursuant to the Company's Open Market Sale AgreementSM with Jefferies, LLC ("Jefferies") dated November 6, 2025 and a shelf registration statement on Form S-3 (File No. 333-291308) previously filed by the Company and declared effective by the Securities and Exchange Commission (the "SEC") on December 8, 2025, which included a prospectus supplement relating to the Company's at the market offering program. The Company currently intends to use the net proceeds from this sale for costs associated with the development of its clinical-stage programs, its discovery research and development activities and additional clinical development, and for general corporate purposes, working capital and capital expenditures. The Company may also use a portion of the remaining net proceeds and its existing cash, cash equivalents and marketable securities to in-license, acquire, or invest in complementary businesses, technologies, products or assets. Following these sales, the Company may offer and sell additional shares of its common stock having an aggregate offering price of up to $62.9 million from time to time through Jefferies pursuant to the Open Market Sale AgreementSM.

This Current Report on Form 8-K contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, as amended. Forward-looking statements can be identified by words such as “anticipate,” “believe,” “continue,” “could,” “estimate,” “expect,” “future,” “goal,” “intend,” “look forward to,” “may,” “plan,” “potential,” “predict,” “project,” “seek,” “strategy,” “should,” “target,” “will,” “would” and similar expressions regarding future periods. These forward-looking statements include, but are not limited to, statements regarding the Company’s intended use of the sale proceeds. Any forward-looking statements in this 8-K are based on management’s current expectations and beliefs and are subject to a number of risks, uncertainties and important factors that may cause actual events or results to differ materially from those expressed or implied by any forward-looking statements contained in this 8-K, including, without limitation, those risks and uncertainties set forth more fully under the caption “Risk Factors” in the Company’s prospectus supplement included in the Company's registration statement on Form S-3 filed with the SEC on November 6, 2025, the Company's most recent Annual Report on Form 10-K filed with the SEC and subsequent filings with the SEC. The Company cautions you not to place undue reliance on any forward-looking statements, which speak only as of the date they are made. The Company disclaims any obligation to publicly update or revise any such statements to reflect any change in expectations or in events, conditions or circumstances on which any such statements may be based, or that may affect the likelihood that actual results will differ from those set forth in the forward-looking statements. Any forward-looking statements contained in this 8-K represent the Company’s views only as of the date hereof and should not be relied upon as representing its views as of any subsequent date.

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.

			MBX BIOSCIENCES, INC.
Date:	February 5, 2026	By:	/s/ P. Kent Hawryluk
			President and Chief Executive Officer (Principal Executive Officer)

FAQ

What did MBX Biosciences (MBX) announce in this 8-K filing?

MBX Biosciences disclosed it completed an at-the-market stock sale, issuing 2,250,986 common shares at a volume weighted average price of $38.76, generating approximately $87.1 million in gross proceeds to support its clinical programs, research activities, and general corporate purposes.

How much capital did MBX Biosciences (MBX) raise and at what share price?

MBX Biosciences raised approximately $87.1 million in gross proceeds by selling 2,250,986 shares of common stock. The shares were issued at a volume weighted average price of $38.76 per share through its at-the-market offering program with Jefferies LLC.

How will MBX Biosciences (MBX) use the proceeds from the share sale?

MBX Biosciences intends to use the net proceeds to fund development of its clinical-stage programs, discovery research and additional clinical development, and for general corporate purposes, working capital and capital expenditures. It may also allocate some funds to in-license, acquire, or invest in complementary businesses or technologies.

What offering structure did MBX Biosciences (MBX) use for this capital raise?

MBX Biosciences used an at-the-market offering program under an Open Market Sale Agreement with Jefferies LLC. Shares were issued pursuant to a previously effective Form S-3 shelf registration statement and related prospectus supplement covering the company’s at-the-market offering program.

How much additional stock can MBX Biosciences (MBX) still sell under its ATM program?

Following the completed sale, MBX Biosciences may still offer and sell additional shares of its common stock with an aggregate offering price of up to $62.9 million. Any such future issuances would also occur through Jefferies under the existing Open Market Sale Agreement.

What risks did MBX Biosciences (MBX) highlight regarding its forward-looking statements?

MBX Biosciences noted that forward-looking statements, including its intended use of proceeds, are subject to risks and uncertainties described under “Risk Factors” in its Form S-3 prospectus supplement, most recent Form 10-K, and subsequent SEC filings, and may differ materially from actual future results.