The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page.

  Names of Reporting Persons

  James Ralph Scapa

  Check the Appropriate Box if a Member of a Group

  (a)  ☐        (b)  ☐

  SEC Use Only

  Citizenship or Place of Organization

  United States

Number of

Shares

  Beneficially  

Owned By

Each

Reporting

Person

With

  Sole Voting Power:

  18,438,691*

  Shared Voting Power:

  0

  Sole Dispositive Power:

  18,438,691*

  Shared Dispositive Power:

  0

  Aggregate Amount Beneficially Owned by Each Reporting Person

  18,438,691*

  Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions):

  ☐

  Percent of Class Represented by Amount in Row (9)

  31.3%*

  Type of Reporting Person

  IN

Based on the information set forth in the Quarterly Report on Form 10-Q of Altair Engineering Inc. (the “Company”) filed with the Securities and Exchange Commission on November 7, 2019, there were 40,473,100 shares of the Company’s Class A common stock, $0.0001 par value per share (the “Class A Common Stock”) outstanding as of October 21, 2019. James Ralph Scapa (“Mr. Scapa”) is the Trustee of the James R. Scapa Declaration of Trust dated March 5, 1987 (the “Scapa Trust”), and the Manager of JRS Investments, LLC (the “JRS LLC” and, collectively with Mr. Scapa and the Scapa Trust, the “Reporting Persons”). As of December 31, 2019 (the “Event Date”), the Reporting Persons may be deemed to beneficially own an aggregate of 18,438,691 shares of Class A Common Stock of the Company. The number of shares of Class A Common Stock reported above includes (i) 11,115,996 shares of Class B common stock, $0.0001 par value per share (the “Class B Common Stock”), of the Company held by the Scapa Trust, (ii) 7,254,004 shares of Class B Common Stock of the Company held by the JRS LLC, (iii) options to purchase 60,000 shares of Common Stock, which were exercisable upon or within sixty (60) days of the Event Date held by the Reporting Person, (iv) 3,691 shares of Common Stock issued pursuant to vested restricted stock units and (v) 5,000 shares of Common Stock to be issued pursuant to vesting of restricted stock units within sixty (60) days of the Event Date held by the Reporting Person, and excludes (i) 30,000 shares of Class A Common Stock to be issued pursuant to vesting of restricted stock units and (ii) 60,000 shares of Class A Common Stock to be issued pursuant to options, each of which were not exercisable upon or within sixty (60) days of the Event Date. The rights of the holders of Class A Common Stock and Class B Common Stock are identical, except with respect to voting and conversion rights. Each share of Class A Common Stock is entitled to one vote per share and each share of Class B Common Stock is entitled to ten votes per share. Each share of Class B Common Stock is immediately convertible, at the option of the Reporting Persons, into one share of Class A Common Stock and shall automatically convert into Class A Common Stock upon the occurrence of certain events. Please see the Company’s Registration Statement filed with the Securities and Exchange Commission on Form S-1 (File No. 333-220710) for a description of the conversion rights. Thus, as of the Event Date, for purposes of Rule 13d-3 under the Securities Exchange Act of 1934, as amended, the Reporting Persons may be deemed to beneficially own 31.3% of the shares of Class A Common Stock issued and outstanding. The percentages were obtained by dividing (a) the number of shares of Class A Common Stock, options, restricted stock units and shares of Class B Common Stock beneficially owned by the Reporting Persons as set forth in Row 9 by (b) the sum of (i) 40,473,100 shares of Class A Common Stock outstanding as of October 21, 2019 and (ii) the 18,438,691 shares of Class A Common Stock and options, restricted stock units and shares of Class B Common Stock that are convertible into Class A Common Stock beneficially owned by the Reporting Persons.

  Names of Reporting Persons

  James R. Scapa Declaration of Trust dated March 5, 1987

  Check the Appropriate Box if a Member of a Group

  (a)  ☐        (b)  ☐

  SEC Use Only

  Citizenship or Place of Organization

  United States

Number of

Shares

  Beneficially  

Owned By

Each

Reporting

Person

With

  Sole Voting Power:

  11,115,996*

  Shared Voting Power:

  0

  Sole Dispositive Power:

  11,115,996*

  Shared Dispositive Power:

  0

  Aggregate Amount Beneficially Owned by Each Reporting Person

  11,115,996*

  Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions):

  ☐

  Percent of Class Represented by Amount in Row (9)

  21.5%*

  Type of Reporting Person

  OO

Based on the information set forth in the Quarterly Report on Form 10-Q of Altair Engineering Inc. (the “Company”) filed with the Securities and Exchange Commission on November 7, 2019, there were 40,473,100 shares of the Company’s Class A common stock, $0.0001 par value per share (the “Class A Common Stock”) outstanding as of October 21, 2019. James Ralph Scapa (“Mr. Scapa”) is the Trustee of the James R. Scapa Declaration of Trust dated March 5, 1987 (the “Scapa Trust”). As of December 31, 2019 (the “Event Date”), Mr. Scapa and the Scapa Trust may be deemed to beneficially own an aggregate of 11,115,996 shares of Class A Common Stock of the Company. The number of shares of Class A Common Stock reported above includes 11,115,996 shares of Class B common stock, $0.0001 par value per share (the “Class B Common Stock”), of the Company. The rights of the holders of Class A Common Stock and Class B Common Stock are identical, except with respect to voting and conversion rights. Each share of Class A Common Stock is entitled to one vote per share and each share of Class B Common Stock is entitled to ten votes per share. Each share of Class B Common Stock is immediately convertible, at the option of the Reporting Persons, into one share of Class A Common Stock and shall automatically convert into Class A Common Stock upon the occurrence of certain events. Please see the Company’s Registration Statement filed with the Securities and Exchange Commission on Form S-1 (File No. 333-220710) for a description of the conversion rights. Thus, as of the Event Date, for purposes of Rule 13d-3 under the Securities Exchange Act of 1934, as amended, Mr. Scapa and the Scapa Trust may be deemed to beneficially own 21.5% of the shares of Class A Common Stock issued and outstanding. The percentages were obtained by dividing (a) the number of shares of Class B Common Stock beneficially owned by Mr. Scapa and the Scapa Trust as set forth in Row 9 by (b) the sum of (i) 40,473,100 shares of Class A Common Stock outstanding as of October 21, 2019 and (ii) the 11,115,996 shares of Class B Common Stock beneficially owned by Mr. Scapa and the Scapa Trust that are convertible into Class A Common Stock.

  Names of Reporting Persons

  JRS Investments, LLC

  Check the Appropriate Box if a Member of a Group

  (a)  ☐        (b)  ☐

  SEC Use Only

  Citizenship or Place of Organization

  United States

Number of

Shares

  Beneficially  

Owned By

Each

Reporting

Person

With

  Sole Voting Power:

  7,254,004*

  Shared Voting Power:

  0

  Sole Dispositive Power:

  7,254,004*

  Shared Dispositive Power:

  0

  Aggregate Amount Beneficially Owned by Each Reporting Person

  7,254,004*

  Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions):

  ☐

  Percent of Class Represented by Amount in Row (9)

  15.2%*

  Type of Reporting Person

  OO

Based on the information set forth in the Quarterly Report on Form 10-Q of Altair Engineering Inc. (the “Company”) filed with the Securities and Exchange Commission on November 7, 2019, there were 40,473,100 shares of the Company’s Class A common stock, $0.0001 par value per share (the “Class A Common Stock”) outstanding as of October 21, 2019. James Ralph Scapa (“Mr. Scapa”) is the Manager of JRS Investments, LLC (the “JRS LLC”). As of December 31, 2019 (the “Event Date”), Mr. Scapa and the JRS LLC may be deemed to beneficially own an aggregate of 7,254,004 shares of Class A Common Stock of the Company. The number of shares of Class A Common Stock reported above includes 7,254,004 shares of Class B common stock, $0.0001 par value per share (the “Class B Common Stock”), of the Company. The rights of the holders of Class A Common Stock and Class B Common Stock are identical, except with respect to voting and conversion rights. Each share of Class A Common Stock is entitled to one vote per share and each share of Class B Common Stock is entitled to ten votes per share. Each share of Class B Common Stock is immediately convertible, at the option of the Reporting Persons, into one share of Class A Common Stock and shall automatically convert into Class A Common Stock upon the occurrence of certain events. Please see the Company’s Registration Statement filed with the Securities and Exchange Commission on Form S-1 (File No. 333-220710) for a description of the conversion rights. Thus, as of the Event Date, for purposes of Rule 13d-3 under the Securities Exchange Act of 1934, as amended, Mr. Scapa and the JRS LLC may be deemed to beneficially own 15.2% of the shares of Class A Common Stock issued and outstanding. The percentages were obtained by dividing (a) the number of shares of Class B Common Stock beneficially owned by Mr. Scapa and the JRS LLC as set forth in Row 9 by (b) the sum of (i) 40,473,100 shares of Class A Common Stock outstanding as of October 21, 2019 and (ii) the 7,254,004 shares of Class B Common Stock beneficially owned by Mr. Scapa and the JRS LLC that are convertible into Class A Common Stock.

Name Of Issuer:

Address of Issuer’s Principal Executive Offices:

Name of Person Filing:

Address of Principal Business Office or, if None, Residence:

Citizenship:

Title of Class of Securities:

CUSIP No.:

If This Statement Is Filed Pursuant to Section 240.13d-1(b) or 240.13d-2(b) or (c), check whether the Person Filing is a:

Ownership:

(a)

(b)

(c)

(i)

(ii)

(iii)

(iv)

(a)

(b)

(c)

(i)

(ii)

(iii)

(iv)

(i)

(ii)

(iii)

(iv)

Ownership of Five Percent or Less of a Class

Ownership of More Than Five Percent on Behalf of Another Person

Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person

Identification and Classification of Members of the Group

Notice of Dissolution of Group

Certification

A power of attorney was previously filed with the Commission and is incorporated herein by reference to Exhibits 99.2, 99.3 and 99.4 to the Schedule 13G filed by James Ralph Scapa on February 14, 2018.

Exhibit No.

Exhibit