MAIA (NYSE American) terminates ATM with H.C. Wainwright after $5.68M raised

Rhea-AI Filing Summary

MAIA Biotechnology, Inc. is amending its shelf to report termination of its at-the-market program covering up to $11,200,000 of common stock. The company reports that, since the prior prospectus dated March 28, 2025, it sold 3,116,012 shares for gross proceeds of $5,680,924 under the sales agreement with H.C. Wainwright & Co.

On May 14, 2026 MAIA suspended sales under the sales agreement and provided notice to terminate the agreement and the related at-the-market offering; termination becomes effective seven business days after May 14, 2026. The supplement also terminates the prior prospectuses on the same schedule. The last reported sale price on the NYSE American was $1.36 per share on May 14, 2026.

Insights

Capital Markets Attorney

Supplement discloses termination of an ATM program and related prospectuses.

The supplement states MAIA is terminating its At The Market Offering Agreement with H.C. Wainwright and ending the prospectuses that supported sales of up to $11,200,000. It records prior activity of 3,116,012 shares sold for $5,680,924.

Timing is explicit: termination is effective seven business days after May 14, 2026. Subsequent SEC filings will show whether MAIA pursues alternative equity programs or amendments to capital-raising arrangements.

Equity Capital Markets Analyst

ATM halted after partial utilization; modest proceeds recorded to date.

The record shows the ATM registered capacity of $11,200,000 and executed sales of 3,116,012 shares raising approximately $5.68M. The agent was H.C. Wainwright under a sales agreement dated February 24, 2024.

Because the supplement terminates the sales agreement effective seven business days after May 14, 2026, future equity issuance under this arrangement will cease unless a new agreement or shelf is filed.

Key Figures

Registered ATM capacity: $11,200,000 Shares sold under agreement: 3,116,012 shares Gross proceeds raised: $5,680,924 +1 more

4 metrics

Registered ATM capacity $11,200,000 prospectus supplement (ATM program)

Shares sold under agreement 3,116,012 shares sales under the sales agreement since March 28, 2025

Gross proceeds raised $5,680,924 proceeds from shares sold under the sales agreement

Last reported sale price $1.36 NYSE American closing price on May 14, 2026

Key Terms

At The Market Offering Agreement, prospectus supplement, sales agreement

3 terms

At The Market Offering Agreement regulatory

"At The Market Offering Agreement dated February 24, 2024"

An at-the-market offering agreement is a contract that lets a company sell newly issued shares directly into the open market through a broker, at whatever price the stock is trading at that moment. For investors this matters because it can increase the number of shares available (which may dilute existing ownership) while providing a flexible, often faster way for the company to raise cash without fixing a price, similar to a vendor selling small batches at current market stalls rather than setting a single fixed price.

prospectus supplement regulatory

"This prospectus supplement amends and supplements the information"

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.

sales agreement regulatory

"suspended sales of our common stock pursuant to the Sales Agreement"

A sales agreement is a written contract that sets out the terms for selling goods, services, or assets, specifying price, delivery, payment schedule and responsibilities of each side. For investors it matters because it creates a predictable stream of revenue or cash obligations, clarifies timing and risk, and can change a company’s value or forecasts much like a signed order turns a customer’s verbal intent into a firm commitment.

Filed Pursuant to Rule 424(b)(5)
Registration No. 333-273984

PROSPECTUS SUPPLEMENT

(To Prospectus dated August 23, 2023)

Up to $11,200,000

Common Stock

MAIA Biotechnology, Inc.

This prospectus supplement amends and supplements the information in the prospectus, dated August 23, 2023, filed as a part of our registration statement on Form S-3 (File No. 333-273984), as supplemented by our prospectus supplements dated February 14, 2024, March 25, 2024, May 15, 2024, December 23, 2024 and March 28, 2025, or the Prior Prospectuses. This prospectus supplement should be read in conjunction with the Prior Prospectuses, and is qualified by reference thereto, except to the extent that the information herein amends or supersedes the information contained in the Prior Prospectuses. This prospectus supplement is not complete without, and may only be delivered or utilized in connection with, the Prior Prospectuses, and any future amendments or supplements thereto.

We filed the Prior Prospectuses to register the offer and sale of our common stock, par value $0.0001 per share, from time to time pursuant to the terms of that certain At The Market Offering Agreement dated February 24, 2024, or the sales agreement, between H.C. Wainwright & Co., LLC, or Wainwright, acting as the agent, and us.

Since filing of the March 28, 2025 prospectus supplement for up to $11,200,000, we have offered and sold 3,116,012 shares of common stock for gross proceeds of approximately $5,680,924 pursuant to the sales agreement.

On May 14, 2026, we suspended sales of our common stock pursuant to the Sales Agreement and provided notice to the Agent that we are terminating the sales agreement and the “at-the-market” offering to which it relates, which termination will be effective 7-business days after May 14, 2026 in accordance with the terms of the sales agreement. We are filing this Supplement to amend and supplement the information in the Prior Prospectuses to report the termination of the sales agreement and the “at-the-market” offering to which it relates and to terminate the Prior Prospectuses, which termination will be effective 7-business days after May 14, 2026 in accordance with the terms of the sales agreement.

Our common stock is listed on the NYSE American under the symbol “MAIA.” On May 14, 2026, the last reported sale price of our common stock on the NYSE American was $1.36 per share.

NEITHER THE SECURITIES AND EXCHANGE COMMISSION NOR ANY STATE SECURITIES COMMISSION HAS APPROVED OR DISAPPROVED OF THESE SECURITIES OR PASSED UPON THE ADEQUACY OR ACCURACY OF THIS PROSPECTUS SUPPLEMENT AND THE ACCOMPANYING PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY IS A CRIMINAL OFFENSE.

H.C. Wainwright & Co.

The date of this prospectus supplement is May 14, 2026

FAQ

What change did MAIA (MAIA) make to its at-the-market offering?

MAIA terminated its at-the-market sales agreement with H.C. Wainwright, effective seven business days after May 14, 2026. The prospectus supplement states the company suspended sales on May 14, 2026 and provided notice to terminate the agreement and related prospectuses.

How much common stock capacity was registered under the prior ATM prospectus?

The prospectus registered up to $11,200,000 of common stock under the at-the-market program. That registered dollar capacity is shown on the prospectus supplement dated May 14, 2026.

How many shares were sold under the sales agreement and what proceeds were raised?

MAIA sold 3,116,012 shares under the sales agreement, generating gross proceeds of approximately $5,680,924, as disclosed in the May 14, 2026 prospectus supplement.

Who acted as agent for the at-the-market sales?

H.C. Wainwright & Co., LLC acted as the agent under a sales agreement dated February 24, 2024, per the prospectus supplement filed May 14, 2026.

Will MAIA continue equity sales under the terminated program after the effective date?

No. The supplement states the sales agreement and the related at-the-market offering will terminate seven business days after May 14, 2026, and the Prior Prospectuses will be terminated on that schedule.