Class A Common Stock, par value $.01 per share

Sphere Entertainment Co.

TWO PENNSYLVANIA PLAZA, NEW YORK, NY, 10121

The disclosure in Item 2(a) is hereby amended to read in its entirety as follows: (a) The names of the Reporting Persons who are Group Members are: James L. Dolan; Thomas C. Dolan; Kathleen M. Dolan, individually and as a Trustee of the Charles F. Dolan Children Trust FBO Kathleen M. Dolan, the Charles F. Dolan Children Trust FBO Deborah Dolan-Sweeney, the Charles F. Dolan Children Trust FBO Marianne Dolan Weber, the Charles F. Dolan Children Trust FBO Thomas C. Dolan and the Charles F. Dolan Children Trust FBO James L. Dolan (hereinafter collectively referred to as the "Dolan Children Trusts" and individually, a "Dolan Children Trust"), and as sole Trustee of the Ryan Dolan 1989 Trust and the Tara Dolan 1989 Trust; Marianne Dolan Weber; Deborah A. Dolan-Sweeney; the Dolan Children Trust FBO Kathleen M. Dolan; the Dolan Children Trust FBO Marianne Dolan Weber; the Dolan Children Trust FBO Deborah Dolan-Sweeney; the Dolan Children Trust FBO James L. Dolan; the Dolan Children Trust FBO Thomas C. Dolan; the Charles F. Dolan 2009 Family Trust FBO James L. Dolan; the Charles F. Dolan 2009 Family Trust FBO Thomas C. Dolan; the Charles F. Dolan 2009 Family Trust FBO Kathleen M. Dolan; the Charles F. Dolan 2009 Family Trust FBO Marianne E. Dolan Weber; the Charles F. Dolan 2009 Family Trust FBO Deborah A. Dolan-Sweeney; the Ryan Dolan 1989 Trust; the Tara Dolan 1989 Trust; and the Charles F. Dolan 2009 Revocable Trust (the "CFD 2009 Trust"). The Reporting Persons also include Corby Dolan Leinauer, as a Trustee of the Charles F. Dolan 2009 Family Trust FBO Thomas C. Dolan, the Charles F. Dolan 2009 Family Trust FBO James L. Dolan, the Charles F. Dolan 2009 Family Trust FBO Marianne E. Dolan Weber, the Charles F. Dolan 2009 Family Trust FBO Kathleen M. Dolan and the Charles F. Dolan 2009 Family Trust FBO Deborah A. Dolan-Sweeney (collectively, the "2009 Family Trusts" and individually, a "2009 Family Trust"), Mary S. Dolan, as a Trustee of the Dolan Children Trust FBO Deborah Dolan-Sweeney and each of the 2009 Family Trusts, and Paul J. Dolan, as a Trustee of the Dolan Children Trusts FBO Kathleen M. Dolan and James L. Dolan. Charles F. Dolan passed away on December 28, 2024 and is no longer a Group Member.

The disclosure in Item 2(b) is hereby amended to remove information related to Charles F. Dolan.

The disclosure in Item 2(c) is hereby amended to remove information related to Charles F. Dolan.

See the Original Schedule 13D, as amended.

See the Original Schedule 13D, as amended.

The disclosure in Item 5(a) and (b) is hereby amended and supplemented as follows: (a) and (b) As of December 31, 2024, the Group Members may be deemed to beneficially own an aggregate of 8,829,140 shares of Class A Common Stock as a result of their beneficial ownership of (i) 1,962,386 shares of Class A Common Stock (inclusive of exercisable options and shares held by the Dolan Family Foundation, for which certain Group Members serve as a director), and (ii) 6,866,754 shares of Class A Common Stock issuable upon conversion of an equal number of shares of Class B Common Stock. This aggregate amount represents approximately 24.4% of the total shares of the Issuer's common stock deemed to be currently outstanding. Group Members in the aggregate may be deemed to have the current shared power to vote or direct the vote of and to dispose of or direct the disposition of 6,866,754 shares of Class A Common Stock issuable upon conversion of an equal number of shares of Class B Common Stock (representing all outstanding Class B Common Stock) because of the terms of the Class B Stockholders' Agreement (as previously defined in the Schedule 13D). Reporting Persons and individuals who are not Group Members but are trustees of trusts that are Group Members may be deemed to beneficially own an additional 58,744 shares of Class A Common Stock. Each of the Reporting Persons disclaims beneficial ownership of the securities held by the other Reporting Persons, and this report shall not be deemed to be an admission that each such person is the beneficial owner of such securities. The percentages used herein with respect to the ownership of Class A Common Stock are calculated based on 28,926,507 outstanding shares of Class A Common Stock as of October 31, 2024, as reported by the Issuer in its Quarterly Report on Form 10-Q that was filed with the Securities and Exchange Commission on November 12, 2024. The information contained in Item 4 of this Amendment No. 4 is incorporated by reference. See the responses to Items 7 through 13 of each cover page to this Amendment No. 4, which are incorporated by reference and provide updated information about the Reporting Persons' beneficial ownership as of December 31, 2024.

See Item 5(a) above

Not applicable.

See the Original Schedule 13D, as amended.

None, except as described herein.