2025 Stock Option Plan

At its June 2025 Annual Meeting of Shareholders, the Company’s 2025 Stock Option and Incentive Plan (“2025 Option Plan”) was approved by the shareholders. The 2025 Option Plan replaced the 2015 Stock Option Plan (“2015 Option Plan”), originally referred to as the 2007 Option Plan. No new awards can be issued under the 2015 Option Plan. The Company reserved

117,868 Common Shares for issuance under the 2025 Option Plan at the time of adoption. On May 20, 2026, the 2025 Option Plan was amended to increase the number of options available for issuance by 900,000 Common Shares. As of June 30, 2026 and December 31, 2025, the Company had 234,814 and 80,686 options available for grant under the 2025 Option Plan and 2015 Option Plan, respectively. The Common Shares underlying any awards under the 2025 Option Plan and 2015 Option Plan that are forfeited, canceled, or otherwise terminated (other than by exercise) are added back to the shares available for issuance under the 2025 Option Plan. Share options are granted in either US$ or C$. Upon the change in the Company’s functional currency, effective July 1, 2023, C$ share options previously classified as equity were reclassified as liabilities. All grants following the Company’s change in functional currency are in US$.

2026 Inducement Plan

On May 28, 2026, the Board of Directors adopted the ProMIS Neurosciences Inc. 2026 Inducement Plan (the “2026 Inducement Plan”), pursuant to which 180,000 common shares were reserved for equity-based awards to eligible individuals as an inducement material to their entering into employment with the Company. The 2026 Inducement Plan was adopted without shareholder approval pursuant to Nasdaq Listing Rule 5635(c)(4). The 2026 Inducement Plan provides for the grant of non-qualified stock options, stock appreciation rights, restricted stock units, restricted stock awards, unrestricted stock awards and dividend equivalent rights. As of June 30, 2026, no awards had been granted and 180,000 common shares remained available for issuance under the 2026 Inducement Plan.

Canadian Dollar Share Options

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The following table summarizes the C$ share options outstanding under the 2025 Option Plan and 2015 Option Plan for the six months ended June 30, 2026. All amounts are denominated in C$, except year and share amounts:

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The aggregate intrinsic value of options outstanding and vested and exercisable is calculated as the difference between the exercise price of the underlying options, and the fair value of the Company’s Common Shares when the exercise price is below fair value. During the six months ended June 30, 2026, no C$ options were exercised or granted, and 486 C$ options expired.

Upon the change in the Company’s functional currency effective July 1, 2023, C$ share options previously classified as equity were reclassified as liabilities. The C$ options were re-measured as of June 30, 2026 and had a fair value of $77,255.

A summary of share-based compensation liability activity, measured using level 3 fair value inputs, for the period ended June 30, 2026 is as follows:

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A summary of share-based compensation liability activity, measured using level 3 fair value inputs, for the year ended December 31, 2025 is as follows:

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The following table summarizes the weighted average of significant assumptions used to calculate the fair value of C$ share options outstanding and exercisable as of June 30, 2026 and December 31, 2025:

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Expected volatility is based on historical volatility of the Company’s Common Shares over the expected life of the option, as the Company’s options are not readily tradable.

US Dollar Share Options

The Company began making share option grants denominated in US$ following the Company’s change in functional currency in July 2023. The following table summarizes the US$ share options outstanding under the 2025 Option Plan and 2015 Option Plan for the six months ended June 30, 2026. All amounts are denominated in US$, except year and share amounts:

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2026 Service-based US$ grants

During the six months ended June 30, 2026, the Company granted 479,101 US$ share options subject solely to service-based vesting conditions with a grant date fair value of $4,312,752.

The fair value of the US$ share options granted subject to solely service-based vesting conditions was estimated using Black-Scholes with the following assumptions:

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2026 Performance-based US$ grants

During the six months ended June 30, 2026, the Company granted 375,001 US$ share options to management and employees with vesting subject to both performance and service conditions (“2026 Performance Options”). The 2026 Performance Options initially vest upon the achievement of specified performance conditions related to the Company's clinical development activities, which must be met prior to June 30, 2027. The 2026 Performance Options had a grant date fair value of $3,310,134 which was estimated using a Black-Scholes model with the following inputs: share price of $10.65, exercise price of $10.77, expected term of 5.7 years, volatility of 109.2% and a risk free rate of 4.22%.

As of June 30, 2026, achievement of the performance conditions was not considered probable, and no share-based compensation expense has been recognized related to the 2026 Performance Options.

DSU Plan

The Company has a Deferred Share Unit plan (“DSU Plan”) for senior officers. Under the DSU Plan, rights to the Company’s Common Shares may be awarded on a deferred payment basis up to a maximum of 667 common share units. Each common share unit will fully vest upon cessation of employment with the Company and then can be redeemed for one common share of the Company by the unitholder. The Company had 42 units outstanding as of June 30, 2026.

Share-based Payment Expense

The following table summarizes total share-based compensation included in the Company’s accompanying unaudited condensed consolidated statements of operations:

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As of June 30, 2026, there was $4,857,071 of unrecognized share-based compensation expense related to US$ options outstanding but unvested, excluding the 2026 Performance Options, which is expected to be recognized over the remaining service period of 3.4 years. There was no unrecognized compensation cost related to the C$ options as of June 30, 2026.