In March 2020, the shareholders approved an amended and restated certificate of incorporation which authorizes MAIA to issue 100,000,000 shares of stock, as follows: 70,000,000 shares of preferred stock and 30,000,000 shares of common stock, all with a par value of $0.0001 per share. The rights, privileges, preferences, and restrictions of the classes of preferred stock have yet to be established. As of June 30, 2022, each of the common stockholders have equal voting rights, and except in the case of restricted common shares, equal rights of participation in dividends and other distributions with other common stockholders.

Among other provisions, MAIA's shareholders agreement gave first MAIA, followed by the non-selling shareholders, the option to purchase the outstanding shares of a shareholder prior to the sale of shares to a third party. Should the non-selling shareholders decline to purchase any portion of the selling shareholders shares, MAIA had a final opportunity to repurchase the shares. The agreement also contains provisions for "drag-along" and "tag-along" rights, as described in the agreement. MAIA’s shareholders agreement, including the aforementioned provisions, terminated upon the closing of MAIA’s initial public offering on August 1, 2022.

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 (see Note 6 for additional information on the issuance of these additional shares).

MAIA Biotechnology, Inc. Restricted Stock Awards

During the six months ended June 30, 2021, MAIA recognized $135,000 of stock compensation expense related to 75,000 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 cancelled 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 June 30, 2022 related to the founder's restricted shares.

During the six months ended June 30, 2021, MAIA recognized $105,000 of stock compensation expense related to the MAIA restricted shares granted to the founder. The issuance of restricted shares in MAIA as a replacement for the shares the founder held in THIO was accounted for as a modification. There was no additional incremental stock compensation recorded as related to the cancellation of the founder's THIO restricted shares and concurrent grant of MAIA restricted shares as the fair value of the original THIO award immediately before the grant of the MAIA restricted shares and the fair value of the replacement award were equal. There were no unvested restricted shares as of June 30, 2022.

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 be exercisable, in whole or in part, during the exercise period ending on 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 the modified awards compared to the original awards immediately prior to the modification was calculated at $450,578 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 approximately $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.

MAIA Biotechnology, Inc. Stock Award Plans

In 2018, the Company adopted the MAIA Biotechnology, Inc. 2018 Stock Option Plan (the "MAIA 2018 Plan"). MAIA's board of directors administers the MAIA Plan, under which 3,900,000 shares of common stock are reserved for stock option issuance, for the purposes of attracting, retaining, and motivating key employees, directors, and consultants of MAIA. The 2018 plan was replaced by the Amended and Restated 2020 Equity Plan. As of June 30, 2022 there are 1,934,500 options outstanding in the 2018 Stock Option Plan.

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 reserved 1,671,000 common shares for issuance, also for the purposes of attracting, retaining, and motivating key employees, directors, and consultants of MAIA. In November 2020, the MAIA 2020 Plan was amended to reserve a total of 3,171,000 shares of common stock. The MAIA 2020 Plan permits awards to take the form of stock options, restricted stock and restricted stock units. In April and July of 2021 there were amendments to the 2020 Plan to bring the plan to a total of 4,171,000 shares reserved for issuance. As of June 30, 2022 there are 3,993,023 options outstanding in the 2020 plan and 174,977 shares available for future issuance under the 2020 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 10 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 7 years. Outstanding options awarded under the MAIA 2020 Plan may, but need not, vest and therefore become exercisable in periodic instalments that may, but need not, be equal. The option may be subject to such 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 cancelled ninety days after termination of an employee, director, founder, or consultant. Unexercised options are cancelled 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 June 30, 2022, only stock options have been awarded pursuant to the MAIA stock award plans.

During the six months ended June 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 value 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 June 30, 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.

During the six months ended June 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 six months ended June 30, 2022 and 2021 was $5.97 and $1.49, respectively. As of June 30, 2022, the total unrecognized compensation related to unvested employee and non-employee stock option awards granted was $2,991,036, which the Company expects to recognize over a weighted average period of approximately 3.1 years.