Upon the closing of the Company’s initial public offering, the Company’s shareholders agreement terminated pursuant to its terms. In connection with the closing of the Company’s initial public offering, the Company amended and restated its Amended and Restated Certificate of Incorporation (the “Amended and Restated Certificate of Incorporation”) and amended and restated its Bylaws (the “Amended and Restated Bylaws”). The Amended and Restated Certificate of Incorporation was filed with the Secretary of State of the State of Delaware on August 1, 2022 and became effective on that date, and among other things, increased the authorized number of common stock to 70,000,000 shares and decreased the authorized number of preferred stock to 30,000,000 shares.

Sales of MAIA Common Stock

During January and February 2022, the Company sold 263,729 shares of common stock at $9.00 per share for gross proceeds of $2,373,561 with no transaction costs. During May 2022, the Company sold 11,111 shares of common stock at $9 per share for gross proceeds of $99,999 with no transaction costs. The Company issued these shareholders additional shares upon the closing of the Company's initial public offering such that the $9.00 price per share they paid was equal to the price per share in the Company's initial public offering of $5.00.The number of Ratchet Shares were calculated using the $5.00 per share price in the Company's initial public offering and 219,872 shares of common stock were issued on August 1, 2022 to the investors in the Recent Private Rounds. The Ratchet shares were determined to be a freestanding instrument that was classified as a liability when the right was granted and subsequently reclassified to equity when shares were issued. The Ratchet Shares were valued at $1,099,360, based on the $5 price of the initial public offering and were recorded as expense included in operating expense.

Initial Public Offering

On July 28, 2022 the Company’s shares of common stock began trading on the NYSE American under the symbol MAIA. On August 1, 2022, the Company sold 2,000,000 shares of common stock at $5.00 per share for gross proceeds of $10,000,000

in an initial public offering prior to deducting underwriting discounts, commissions, and other offering expenses. On August 3, 2022, the Company sold an additional 300,000 shares of common stock at $5.00 per share when the underwriter exercised the overallotment for gross proceeds of $1,500,000 prior to deducting underwriting discounts, commissions, and other offering expenses. After deducting the underwriting discount and other offering expenses payable by the Company, the total net proceeds for the initial public offering and the overallotment were approximately $9.1 million.

MAIA Biotechnology, Inc. Restricted Stock Awards

During the nine months ended September 30, 2021, MAIA recognized $202,500 of stock compensation expense related to 112,500 of MAIA’s restricted shares granted to the founders. On August 13, 2021, upon the dissolution of THIO and merger into MAIA (see Note 1), a founder’s 612,500 fully vested THIO restricted shares were canceled and the founder was issued 612,500 MAIA restricted shares. Additionally, in accordance with the founder's original award, the founder was also issued 87,500 MAIA restricted shares which vested ratably each quarter through April 1, 2022 to replace the equivalent number of unvested THIO restricted shares. There are no unvested shares as of September 30, 2022 related to the founder's restricted shares.

MAIA Stock Warrants

In January 2022, the Company and certain warrant holders executed waivers related to the acceptance and approval of an amendment to the holders’ warrant agreements originally issued between May 6, 2020 and February 26, 2021 in connection with the Company’s issuance of convertible notes. The amendment removed the IPO expiration provision from the warrant agreements, and the warrants are now only to be exercisable, in whole or in part, during the exercise period ending on the earliest to occur of: (a) various dates in 2028 as stated within the warrant agreements; or (b) immediately prior to the closing of a change of control. The value of the warrant modification to the 144,497 warrants was calculated using the Black-Scholes-Merton option pricing model. The incremental fair value attributable to the modified awards compared to the original awards immediately prior to the modification was calculated at $450,578 and was treated as a deemed dividend for the three months ended March 31, 2022 and is reflected as “Deemed dividend on warrant modification” in the accompanying statement of operations.

During January 2022, warrants were exercised, resulting in the issuance of 61,111 shares of MAIA common stock for proceeds of $110,000. During May 2022, warrants were exercised, resulting in the issuance of 153,000 shares of common stock for proceeds of approximately $275,400. Another 394,501 warrants were exercised with a cashless exercise assuming the fair market value of $9 per share resulting in the issuance of 315,601 shares of common stock.

On August 1, 2022 at the closing of the initial public offering, 20,520 warrants with an exercise price of $5.00 per share expired.

Concurrently with the closing of the Company’s initial public offering, the Company issued warrants to purchase an aggregate of up to 100,000 shares of its common stock to the Representative or its designees, at an exercise price of $6.25 per share (the “Representative’s Warrants”). The Representative’s Warrants are exercisable beginning on January 23, 2023, and expire on July 27, 2027, pursuant to the terms and conditions of the Representative’s Warrants. On August 3, concurrently with the full exercise of the Underwriter’s over-allotment option, the Company issued additional warrants to purchase an aggregate of up to 15,000

shares of its common stock to the Representative or its designees on the same terms. The warrants are not indexed to the Company’s own stock and therefore meet the definition of a derivative liability. The warrants are liability classified instruments and were initially recorded as $343,735, which was the value determined using the Black-Scholes method using a term of five years, risk free interest rate of 2.82% and volatility of 77.5%. As of September 30, 2022 the Company remeasured the warrant liability resulting in a value of $215,705. The gain on remeasurement of the warrant liability in the amount of $128,030 was included in other income (expense) net.

MAIA Biotechnology, Inc. Stock Award Plans

In 2018, the Company adopted the MAIA Biotechnology, Inc. 2018 Stock Option Plan (the “MAIA 2018 Plan”). MAIAs board of directors administers the MAIA Plan for the purposes of attracting, retaining, and motivating key employees, directors, and consultants of MAIA. The terms of the MAIA 2018 Plan continue to govern the 1,924,500 options outstanding in the plan of September 30, 2022.

In 2020, the Company adopted the MAIA Biotechnology, Inc. Amended and Restated 2020 Equity Incentive Plan (the “MAIA 2020 Plan’’), also administered by the board of directors. The MAIA 2020 Plan permitted awards to take the form of stock options, restricted stock and restricted stock units. The terms of the MAIA 2020 Plan continue to govern the 3,993,023 options outstanding in the plan as of September 30, 2022. There are no shares reserved for future issuance in the MAIA 2018 Plan or the MAIA 2020 Plan .

On August 1, 2022 the Company approved the MAIA Biotechnology, Inc. 2021 Equity Incentive Plan (the “MAIA 2021 Plan’’) with 1,909,518 shares of common stock reserved for issuance. As of September 30, 2022 there are 1,315,131 available for future issuance under the MAIA 2021 Plan and 594,387 options are outstanding in the MAIA 2021 Plan.

Stock options are to be granted with an exercise price which is at least equal to the stock’s estimated fair value at the date of grant, and with a contractual term of no more than ten years from the date of grant. In the case of an option granted to a 10% stockholder, the exercise price shall be generally no less than 110% of the fair market value per share on the date of grant, and the contractual term shall be seven years. Outstanding options awarded under the MAIA 2021 Plan may, but need not, vest and therefore become exercisable in periodic installments that may, but need not, be equal. The option may be subject to other terms and conditions as to the time or times when it may be exercised (which may be based on performance or other criteria) as the board of directors may deem appropriate. Unexercised options are canceled ninety days after termination of an employee, director, founder, or consultant. Unexercised options are canceled immediately if an employee, director, founder, or consultant is terminated for cause; under certain other circumstances, the period to cancellation may differ as described in the respective plan documents. Certain clauses in the Plans also govern the Company’s exercise repurchase rights and various other features of awards granted under the plans.

As of September 30, 2022, only stock options have been awarded pursuant to the MAIA stock award plans.

During the nine months ended September 30, 2022, the fair value of the Company’s common stock was estimated for financial reporting purposes from January 1 to January 26, 2022 based on valuations of $8.87 per share as of December 31, 2021. For our valuations of common stock performed, we used a hybrid method of the Option Pricing Method (“OPM”) and the Probability-Weighted Expected Return Method (“PWERM”). PWERM considers various potential liquidity outcomes. Our approach included the use of an initial public offering scenario, a scenario assuming continued operation as a private entity, and a dissolution scenario. Under the hybrid OPM and PWERM, the per share values calculated under the OPM and PWERM are weighted based on expected exit outcomes and the quality of the information specific to each allocation methodology to arrive at a final estimated fair value per share of the common stock before a discount for lack of marketability is applied. From January 27 to May 31, 2022 the fair value of the Company’s common stock was estimated for financial reporting purposes at $9 per share based on the sale of common stock from January 27, 2022 to May 19, 2022. From June 1, 2022 to August 1, 2022 the fair value of the Company's common stock was estimated for financial reporting purpose at $5 per share based on the price paid in the initial public offering.

During the nine months ended September 30, 2021, the fair value of the Company’s common stock was estimated for financial reporting purposes based on valuations. From January 1, 2021 to February 28, 2021 a valuation of $1.80 was used. During the period of March 1, 2021 to June 6, 2021, the fair value of the Company’s common stock was estimated for financial reporting purposes based on valuations of $1.83 per share in February and April 2021 due to the lack of any single specific event that would have indicated a definitive change in the value of the Company. The February and April 2021 valuations used the income approach and the market approach in estimating the fair value of our common stock. The market approach utilized guideline public companies in estimating fair value of our stock. The income approach estimates enterprise value based on the estimated present value of future cash flows the business is expected to generate over its remaining life. The estimated present value is calculated using a discount rate reflective of the risks associated with an investment in a similar company in a similar industry or having a similar history of revenue growth. The market approach measures the value of a business through an analysis of recent sales or offerings of comparable investments or assets, and in our case, focused on comparing us to a group of our peer companies. In applying this method, valuation multiples are derived from historical and projected operating data of the peer company group. We then apply the selected multiples to our operating data to arrive at a range of indicated enterprise values of the Company. We then subtracted the net debt to determine equity value.

The weighted-average grant date fair value of stock options issued during the nine months ended September 30, 2022 and 2021 was $3.11 and $2.57, respectively. As of September 30, 2022, the total unrecognized compensation related to unvested employee and non-employee stock option awards granted was $3,829,045, which the Company expects to recognize over a weighted average period of approximately 3.4 years.