Viacom (VIAWE) 8-K Viacom and CBS Announce Update on Merger Approval

Exhibit 99.1

VIACOM AND CBS ANNOUNCE UPDATE ON MERGER APPROVAL

SEC Declares FormS-4 Effective, National Amusements Approves Transaction

Merger Now Expected to Close by Early December

NEW YORK, NY, October 28, 2019 — CBS Corporation (NYSE: CBS.A, CBS) and Viacom Inc. (NASDAQ: VIAB, VIA) today announced that the registration statement on FormS-4(No. 333-234238) (the “Registration Statement”) filed by CBS with the U.S. Securities and Exchange Commission (the “SEC”) was declared effective by the SEC on October 25, 2019. The Registration Statement was filed in connection with the proposed combination of CBS and Viacom (the “merger”) and includes a joint consent solicitation statement/prospectus of CBS and Viacom.

The companies also announced that their pending merger and the related proposals have been approved by National Amusements, Inc. and its affiliate, which satisfies the closing conditions to the merger requiring approval of a majority of the CBS Class A shares and a majority of the Viacom Class A shares. The final results of the consent solicitations of CBS and Viacom will be set forth in the companies’ separate Current Reports on Form8-K that will be filed with the SEC.

The completion of the merger remains subject to other customary closing conditions and is now expected to close by early December. At closing, CBS will be renamed “ViacomCBS Inc.” (“ViacomCBS”). In addition, at closing, CBS will delist its Class A and Class B common stock from NYSE and will list ViacomCBS Class A and Class B common stock, including the outstanding shares of CBS Class A and Class B common stock (which will remain outstanding shares of ViacomCBS), on The NASDAQ Stock Market under the new ticker symbols “VIACA” and “VIAC,” respectively.

About CBS

CBS Corporation (NYSE: CBS.A and CBS) is a mass media company that creates and distributes industry-leading content across a variety of platforms to audiences around the world. The Company has businesses with origins that date back to the dawn of the broadcasting age as well as new ventures that operate on the leading edge of media. CBS owns the most-watched television network in the U.S. and one of the world’s largest libraries of entertainment content, making its brand –“the Eye” – one of the most-recognized in business. The Company’s operations span virtually every field of media and entertainment, including cable, publishing, local TV, film and interactive. CBS’ businesses include CBS Television Network, The CW (a joint venture between CBS Corporation and Warner Bros. Entertainment), Network 10 Australia, CBS Television Studios, CBS Global Distribution Group, CBS Consumer Products, CBS Home Entertainment, CBS Interactive, CBS All Access, the Company’sdirect-to-consumer digital streaming subscription service, CBS Sports Network, CBS Films, Showtime Networks, Pop, Smithsonian Networks, Simon & Schuster, CBS Television Stations and CBS Experiences. For more information, go tohttp://www.cbscorporation.com.

About Viacom

Viacom (NASDAQ: VIAB, VIA) creates entertainment experiences that drive conversation and culture around the world. Through television, film, digital media, live events, merchandise and solutions, its brands connect with diverse, young and young at heart audiences in more than 180 countries.

For more information on Viacom and its businesses, visit http://www.viacom.com. Keep up with Viacom news by following it on Twitter (twitter.com/Viacom), Facebook (facebook.com/Viacom) and LinkedIn (linkedin.com/company/Viacom).

Important Information About the Proposed Merger Between CBS and Viacom and Where To Find It

In connection with the proposed merger between CBS Corporation (“CBS”) and Viacom Inc. (“Viacom”), CBS has filed with the Securities and Exchange Commission (the “SEC”) a Registration Statement on FormS-4(No. 333-234238) (the “Registration Statement”) that includes a joint consent solicitation statement of CBS and Viacom and that also constitutes a prospectus of CBS (the “joint consent solicitation statement / prospectus”). The Registration Statement was declared effective by the SEC on October 25, 2019. CBS and Viacom commenced mailing the definitive joint consent solicitation statement / prospectus to CBS stockholders and Viacom stockholders on or about October 28, 2019. This communication is not a substitute for the joint consent solicitation statement / prospectus or Registration Statement or any other document which CBS or Viacom may file with the SEC. INVESTORS AND SECURITY HOLDERS OF CBS AND VIACOM ARE URGED TO READ THE REGISTRATION STATEMENT, WHICH INCLUDES THE JOINT CONSENT SOLICITATION STATEMENT / PROSPECTUS, AND ANY OTHER RELEVANT DOCUMENTS THAT ARE FILED OR WILL BE FILED WITH THE SEC, AS WELL AS ANY AMENDMENTS OR SUPPLEMENTS TO THESE DOCUMENTS, CAREFULLY AND IN THEIR ENTIRETY BECAUSE THEY CONTAIN OR WILL CONTAIN IMPORTANT INFORMATION ABOUT THE PROPOSED MERGER AND RELATED MATTERS. Investors and security holders may obtain free copies of the Registration Statement, which includes the joint consent solicitation statement / prospectus, and other documents filed with the SEC by CBS and Viacom through the website maintained by the SEC atwww.sec.gov or by contacting the investor relations department of CBS(+1-212-975-4321 or+1-877-227-0787;investorrelations@CBS.com) or Viacom(+1-212-846-6700 or+1-800-516-4399;investor.relations@Viacom.com).

Participants in the Solicitation

CBS and Viacom and their respective directors and executive officers may be deemed to be participants in the solicitation of consents in respect of the proposed merger. Information regarding CBS’ directors and executive officers, including a description of their direct interests, by security holdings or otherwise, is contained in CBS’ Form10-K for the fiscal year ended December 31, 2018 and its proxy statement filed on April 12, 2019, both of which are filed with the SEC. Information regarding Viacom’s directors and executive officers, including a description of their direct interests, by security holdings or otherwise, is contained in Viacom’s Form10-K for the fiscal year ended September 30, 2018 and its proxy statement filed on January 25, 2019, both of which are filed with the SEC. A more complete description and information regarding directors and executive officers are included in the joint consent solicitation statement / prospectus or will be included in other documents filed with the SEC when they become available. These documents (when available) may be obtained free of charge from the SEC’s website atwww.sec.gov.

No Offer or Solicitation

This communication is for informational purposes only and is not intended to and does not constitute an offer to subscribe for, buy or sell, or the solicitation of an offer to subscribe for, buy or sell, or an invitation to subscribe for, buy or sell any securities or a solicitation of any vote or approval in any jurisdiction, nor shall there be any sale, issuance or transfer of securities in any jurisdiction in which such offer, invitation, sale or solicitation would be unlawful prior to registration or qualification under the securities laws of any such jurisdiction. No offer of securities shall be made except by means of a prospectus meeting the requirements of Section 10 of the Securities Act of 1933, as amended, and otherwise in accordance with applicable law.

Cautionary Notes on Forward-Looking Statements

This communication contains “forward-looking statements” within the meaning of the federal securities laws, including Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. In this context, forward-looking statements often address expected future business and financial performance and financial condition, and often contain words such as “expect,” “anticipate,” “intend,” “plan,” “believe,” “seek,” “see,” “will,” “would,” “may,” “target,” similar expressions and variations or negatives of these words. Forward-looking statements by their nature

address matters that are, to different degrees, uncertain, such as statements about the consummation of the proposed merger and the anticipated benefits thereof. These and other forward-looking statements are not guarantees of future results and are subject to risks, uncertainties and assumptions that could cause actual results to differ materially from those expressed in any forward-looking statements, including the failure to consummate the proposed merger or to make any filing or take other action required to consummate such transaction in a timely matter or at all. Important risk factors that may cause such a difference include, but are not limited to: (i) the proposed merger may not be completed on anticipated terms and timing, (ii) a condition to closing of the proposed merger may not be satisfied, including obtaining regulatory approvals, (iii) the anticipated tax treatment of the proposed merger may not be obtained, (iv) the potential impact of unforeseen liabilities, future capital expenditures, revenues, costs, expenses, earnings, synergies, economic performance, indebtedness, financial condition and losses on the future prospects, business and management strategies for the management, expansion and growth of the combined business after the consummation of the proposed merger, (v) litigation relating to the proposed merger against CBS, Viacom or their respective directors, (vi) potential adverse reactions or changes to business relationships resulting from the announcement or completion of the proposed merger, (vii) any negative effects of the announcement, pendency or consummation of the proposed merger on the market price of CBS’ or Viacom’s common stock and on CBS’ or Viacom’s operating results, (viii) risks associated with third party contracts containing consent and/or other provisions that may be triggered by the proposed merger, (ix) the risks and costs associated with the integration of, and the ability of CBS and Viacom to integrate, the businesses successfully and to achieve anticipated synergies, (x) the risk that disruptions from the proposed merger will harm CBS’ or Viacom’s business, including current plans and operations, (xi) the ability of CBS or Viacom to retain and hire key personnel and uncertainties arising from leadership changes, (xii) legislative, regulatory and economic developments, (xiii) the other risks described in CBS’ and Viacom’s most recent annual reports on Form10-K and quarterly reports on Form10-Q, and (xiv) management’s response to any of the aforementioned factors.

These risks, as well as other risks associated with the proposed merger, are more fully discussed in the joint consent solicitation statement / prospectus included in the Registration Statement. While the list of factors presented here and the list of factors presented in the Registration Statement are considered representative, no such list should be considered to be a complete statement of all potential risks and uncertainties. Unlisted factors may present significant additional obstacles to the realization of forward-looking statements. Consequences of material differences in results as compared with those anticipated in the forward-looking statements could include, among other things, business disruption, operational problems, financial loss, legal liability to third parties and similar risks, any of which could have a material adverse effect on CBS’ or Viacom’s consolidated financial condition, results of operations, credit rating or liquidity. Neither CBS nor Viacom assumes any obligation to publicly provide revisions or updates to any forward-looking statements, whether as a result of new information, future developments or otherwise, should circumstances change, except as otherwise required by securities and other applicable laws.

Media:

CBS

Dana McClintock

(212) 975-1077

dlmcclintock@cbs.com

Viacom

Justin Dini

(212) 846-2724

justin.dini@viacom.com

Investors:

CBS

Anthony DiClemente

(212) 975-2160

anthony.diclemente@cbs.com

Viacom

James Bombassei

(212) 258-6377

james.bombassei@viacom.com

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