John May - 23 Dec 2021 Form 3 Insider Report for Fathom Digital Manufacturing Corp

Footnote F1

On December 23, 2021 (the "Effective Time"), the Issuer, formerly known as Altimar Acquisition Corp. II, acquired Fathom Holdco, LLC ("Fathom") pursuant to a Business Combination Agreement by and among the Issuer, Fathom and certain other parties thereto (the "Business Combination Agreement"). Pursuant to the Business Combination Agreement, at the Effective Time, the outstanding equity interests of Fathom held by the Reporting Person were converted into the right to receive shares of the Issuer's Class A Common Stock or a combination of the Issuer's Class B Common Stock and a like number of Fathom's Class A LLC Units, as applicable. Shares of Class B Common Stock have no economic rights (other than the right to receive the par value of such shares in connection with the liquidation, dissolution or winding up of the Issuer), and each share of Class B Common Stock entitles its holder to one vote per share.

Footnote F2

Mr. May is a director of the Issuer and sole managing member of CORE Industrial Fund Partners GP I, LLC ("CORE Fund I GP"). CORE Fund I GP is the sole general partner of each of CORE Industrial Partners Fund I, LP ("CORE Fund I") and CORE Industrial Partners Fund I Parallel, LP ("CORE Fund I Parallel", and collectively with CORE Fund I, the "CORE Funds"). Consequently, Mr. May and CORE Fund I GP may be deemed the beneficial owners of the shares held by the CORE Funds, but each disclaims beneficial ownership of such securities except to the extent of their pecuniary interest therein.

Footnote F3

The Reporting Person holds an aggregate of 4,717,507 shares of Class B Common Stock and 4,717,507 Class A LLC Units that are subject to forfeiture. These earnout shares will vest in three equal tranches, with each tranche vesting at each of the following share price thresholds: $12.50, $15.00 and $20.00. The achievement of the price threshold will be determined based on a volume-weighted average price ("VWAP") of the Class B Common Stock or Class A LLC Units, as applicable, for 20 trading days within any 30 trading day period or a change of control transaction of the issuer that implies the same per share value as the applicable price threshold. The earnout period will be five years from the date of the closing of the Business Combination or December 23, 2026. If such vesting requirements are not achieved during the five-year earnout period, such earnout shares will be forfeited.

Footnote F4

The Class A LLC Units are exchangeable (upon delivery of a corresponding number of shares of the Issuer's Class B Common Stock (as reported on Table I hereof)) for shares of the Issuer's Class A Common Stock on a one-for-one basis or an equivalent amount of cash at the option of Fathom pursuant to the terms of the Second Amended and Restated LLC Operating Agreement of Fathom.

Footnote F5

The Reporting Person holds an aggregate of 1,668,834 shares of Class A Common Stock that are subject to forfeiture. These earnout shares will vest in three equal tranches, with each tranche vesting at each of the following share price thresholds: $12.50, $15.00 and $20.00. The achievement of the price threshold will be determined based on a VWAP of the Class A common stock for 20 trading days within any 30 trading day period or a change of control transaction of the issuer that implies the same per share value as the applicable price threshold. The earnout period will be five years from the date of the closing of the Business Combination or December 23, 2026. If such vesting requirements are not achieved during the five-year earnout period, such earnout shares will be forfeited.