Lynnette C. Fallon - 15 May 2023 Form 4 Insider Report for AXCELIS TECHNOLOGIES INC (ACLS)

Footnote F1

These shares are issuable on vesting of restricted stock units granted under the Company's 2012 Equity Incentive Plan. Assuming continuation of employment, 25% of these restricted stock units will vest on each of May 15, 2024, May 15, 2025, May 15, 2026 and May 15, 2027.

Footnote F2

Of the shares held after this first grant on May 15, 2023, 26,373 were issuable on vesting of restricted stock units granted to the executive under the 2012 Equity Incentive Plan and are subject to forfeiture.

Footnote F3

In this grant under the Company's 2012 Equity Incentive Plan, the executive may earn shares of common stock, ranging from zero to 150% of the granted units. The shares are earned based on the achievement of 2023 performance goals. Assuming continuation of employment,50% of the earned shares will vest on February 28, 2024 and 50% of the earned shares will vest on February 28, 2025. Unearned restricted stock units will forfeit on February 28, 2024.

Footnote F4

Of the shares held after this second grant on May 15, 2023, 29,073 shares were issuable on vesting of restricted stock units granted to the executive under the 2012 Equity Incentive Plan and are subject to forfeiture.

Footnote F5

These shares were withheld by the Company to cover the tax withholding obligations of the executive on the vesting of restricted stock units.

Footnote F6

Represents the closing price of the common stock on the date of the tax withholding.

Footnote F7

Of the shares held after this first tax withholding forfeiture (and related vesting) on May 15, 2023, 26,226 shares were issuable on vesting of restricted stock units granted to the executive under the 2012 Equity Incentive Plan and are subject to forfeiture.

Footnote F8

Of the shares held after this second tax withholding forfeiture (and related vesting) on May 15, 2023, 23,502 shares were issuable on vesting of restricted stock units granted to the executive under the 2012 Equity Incentive Plan and are subject to forfeiture.

Footnote F9

The price reported in Column 4 is a weighted-average price. These shares were sold in multiple transactions at prices ranging from $129.65 to $130.15, inclusive. The reporting person undertakes to provide to Axcelis Technologies, Inc., any security holder of Axcelis Technologies, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price.

Footnote F10

Of the shares held after this sale on May 16, 2023, 23,502 were issuable on vesting of restricted stock units granted to the director under the 2012 Equity Incentive Plan and are subject to forfeiture.