Name of Joint Filer:

Berkshire Partners LLC

Address of Joint Filer:

200 Clarendon Street

35th Floor

Boston, MA 02116-5021

Issuer Name and Ticker or Trading Symbol:

Portillo’s, Inc. [PTLO]

Date of Earliest Transaction

(Month/Day/Year):

4/15/2025

Designated Filer:

Berkshire Partners LLC

Signature:

Berkshire Partners LLC

By: BPSP, L.P., its managing member

By: Berkshire Partners Holdings LLC, its general partner

/s/ Sharlyn C. Musslewhite

Name: Sharlyn C. Musslewhite

Title: Managing Director

4/17/2025

Date

Name of Joint Filer:

Berkshire Fund VIII-A, L.P.

Address of Joint Filer:

200 Clarendon Street

35th Floor

Boston, MA 02116-5021

Issuer Name and Ticker or Trading Symbol:

Portillo’s, Inc. [PTLO]

Date of Earliest Transaction

(Month/Day/Year):

4/15/2025

Designated Filer:

Berkshire Partners LLC

Signature:

Berkshire Fund VIII-A, L.P.

By Eighth Berkshire Associates LLC,

its general partner

/s/ Sharlyn C. Musslewhite

Name: Sharlyn C. Musslewhite

Title: Managing Director

4/17/2025

Date

Name of Joint Filer:

Berkshire Fund VIII, L.P.

Address of Joint Filer:

200 Clarendon Street

35th Floor

Boston, MA 02116-5021

Issuer Name and Ticker or Trading Symbol:

Portillo’s, Inc. [PTLO]

Date of Earliest Transaction

(Month/Day/Year):

4/15/2025

Designated Filer:

Berkshire Partners LLC

Signature:

Berkshire Fund VIII, L.P.

By Eighth Berkshire Associates LLC,

its general partner

/s/ Sharlyn C. Musslewhite

Name: Sharlyn C. Musslewhite

Title: Managing Director

4/17/2025

Date

Name of Joint Filer:

Berkshire Investors III LLC

Address of Joint Filer:

200 Clarendon Street

35th Floor

Boston, MA 02116-5021

Issuer Name and Ticker or Trading Symbol:

Portillo’s, Inc. [PTLO]

Date of Earliest Transaction

(Month/Day/Year):

4/15/2025

Designated Filer:

Berkshire Partners LLC

Signature:

Berkshire Investors III LLC

/s/ Sharlyn C. Musslewhite

Name: Sharlyn C. Musslewhite

Title: Managing Director

4/17/2025

Date

Name of Joint Filer:

Berkshire Investors IV LLC

Address of Joint Filer:

200 Clarendon Street

35th Floor

Boston, MA 02116-5021

Issuer Name and Ticker or Trading Symbol:

Portillo’s, Inc. [PTLO]

Date of Earliest Transaction

(Month/Day/Year):

4/15/2025

Designated Filer:

Berkshire Partners LLC

Signature:

Berkshire Investors IV LLC

/s/ Sharlyn C. Musslewhite

Name: Sharlyn C. Musslewhite

Title: Managing Director

4/17/2025

Date

Name of Joint Filer:

Eighth Berkshire Associates LLC

Address of Joint Filer:

200 Clarendon Street

35th Floor

Boston, MA 02116-5021

Issuer Name and Ticker or Trading Symbol:

Portillo’s, Inc. [PTLO]

Date of Earliest Transaction

(Month/Day/Year):

4/15/2025

Designated Filer:

Berkshire Partners LLC

Signature:

Eighth Berkshire Associates LLC

/s/ Sharlyn C. Musslewhite

Name: Sharlyn C. Musslewhite

Title: Managing Director

4/17/2025

Date

Name of Joint Filer:

Berkshire Partners Holdings LLC

Address of Joint Filer:

200 Clarendon Street

35th Floor

Boston, MA 02116-5021

Issuer Name and Ticker or Trading Symbol:

Portillo’s, Inc. [PTLO]

Date of Earliest Transaction

(Month/Day/Year):

4/15/2025

Designated Filer:

Berkshire Partners LLC

Signature:

Berkshire Partners Holdings LLC

/s/ Sharlyn C. Musslewhite

Name: Sharlyn C. Musslewhite

Title: Managing Director

4/17/2025

Date

Name of Joint Filer:

BPSP, L.P.

Address of Joint Filer:

200 Clarendon Street

35th Floor

Boston, MA 02116-5021

Issuer Name and Ticker or Trading Symbol:

Portillo’s, Inc. [PTLO]

Date of Earliest Transaction

(Month/Day/Year):

4/15/2025

Designated Filer:

Berkshire Partners LLC

Signature:

BPSP, L.P.

By: Berkshire Partners Holdings LLC, its general partner

/s/ Sharlyn C. Musslewhite

Name: Sharlyn C. Musslewhite

Title: Managing Director

4/17/2025

Date