Item 7.01 Regulation FD Disclosure.
Attached as Exhibit 99.1 to this Current
Report on Form 8-K (this “Current Report”), and incorporated into this Item 7.01 by reference, is a press release
issued by Horizon Acquisition Corp., a Cayman Islands exempted company (“Horizon”), on October 14, 2021, announcing that
Eldridge Industries, LLC, an affiliate of Horizon's sponsor, Horizon Sponsor, LLC, has entered into an agreement with DraftKings Inc.
(“DraftKings”) to make a private placement PIPE investment in connection with the closing of the previously announced
merger between Horizon and Vivid Seats Inc. The investment will be part of the previously announced PIPE financing for the transaction,
with DraftKings assuming a portion of Eldridge's commitment.
The foregoing (including Exhibits 99.1) is
being furnished pursuant to Item 7.01 and will not be deemed to be filed for purposes of Section 18 of the Securities and Exchange
Act of 1934, as amended (the “Exchange Act”), or otherwise be subject to the liabilities of that section, nor will
it be deemed to be incorporated by reference in any filing under the Securities Act of 1933, as amended (the “Securities Act”),
or the Exchange Act.
About Horizon Acquisition Corporation
Horizon is a blank check company formed for the
purpose of effecting a merger, share exchange, asset acquisition, share purchase, reorganization or similar business combination with
one or more businesses. Horizon is sponsored by the Sponsor, an affiliate of Eldridge Industries, LLC (“Eldridge”). Horizon
is led by Todd L. Boehly, the Co-founder, Chairman and Chief Executive Officer of Eldridge. Horizon’s securities are traded on NYSE
under the ticker symbols HZAC, HZAC WS and HZAC.U. Learn more at https://www.horizonacquisitioncorp.com/.
About Vivid Seats
Founded in 2001, Vivid Seats is a leading online
ticket marketplace committed to becoming the ultimate partner for connecting fans to the live events, artists, and teams they love. Based
on the belief that everyone should “Experience It Live”, the Chicago-based company provides exceptional value by providing
one of the widest selections of events and tickets in North America and an industry leading Vivid Seats Rewards program where all fans
earn on every purchase. Vivid Seats has been chosen as the official ticketing partner by some of the biggest brands in the entertainment
industry including ESPN, Rolling Stone, and the Los Angeles Clippers. Through its proprietary software and unique technology, Vivid Seats
drives the consumer and business ecosystem for live event ticketing and enables the power of shared experiences to unite people. Vivid
Seats is recognized by Newsweek as America’s Best Company for Customer Service in ticketing. Fans who want to have the best live
experiences can start by downloading the Vivid Seats mobile app, going to vividseats.com, or calling at 866-848-8499.
Additional Information about the Business Combination
and Where to Find It
In connection with the proposed business combination,
Horizon has filed a registration statement with the SEC on Form S-4, which was declared effective on September 23, 2021, and includes
a proxy statement/prospectus, and certain other related documents, to be used at the meeting of stockholders to approve the proposed business
combination. INVESTORS AND SECURITY HOLDERS OF HORIZON ACQUISITION CORPORATION ARE URGED TO READ THE DEFINITIVE PROXY STATEMENT/PROSPECTUS
AND OTHER RELEVANT DOCUMENTS THAT ARE FILED WITH THE SEC CAREFULLY AND IN THEIR ENTIRETY WHEN THEY BECOME AVAILABLE BECAUSE THEY WILL
CONTAIN IMPORTANT INFORMATION ABOUT VIVID SEATS, HORIZON AND THE BUSINESS COMBINATION. The definitive proxy statement/prospectus was mailed
to shareholders of Horizon as of a record date of September 7, 2021 established for voting on the proposed Business Combination. Investors
and security holders will also be able to obtain copies of the Registration Statement and other documents containing important information
about each of the companies once such documents are filed with the SEC, without charge, at the SEC’s website at www.sec.gov.
Participants in the Solicitation
Horizon and its directors and executive officers
may be deemed participants in the solicitation of proxies from Horizon’s members with respect to the proposed business combination.
A list of the names of those directors and executive officers and a description of their interests in Horizon is contained in Horizon’s
filings with the SEC, including Horizon’s annual report on Form 10-K for the fiscal year ended December 31, 2020, which was filed
with the SEC on March 31, 2021 and amended on May 10, 2021, and is available free of charge at the SEC’s web site at www.sec.gov,
or by directing a request to Horizon Acquisition Corporation, 600 Steamboat Road, Suite 200, Greenwich, CT 06830. Additional information
regarding the interests of such participants will be set forth in the Registration Statement for the proposed business combination when
available. Vivid Seats and its directors and executive officers may also be deemed to be participants in the solicitation of proxies from
the shareholders of Horizon in connection with the proposed business combination. A list of the names of such directors and executive
officers and information regarding their interests in the business combination will be contained in the Registration Statement for the
proposed Business Combination when available.
Caution Concerning Forward-Looking Statements
Certain statements made in this Current Report
on Form 8-K are “forward looking statements” within the meaning of the “safe harbor” provisions of the United
States Private Securities Litigation Reform Act of 1995. When used in this Current Report on Form 8-K, the words “estimates,”
“projected,” “expects,” “anticipates,” “forecasts,” “plans,” “intends,”
“believes,” “seeks,” “may,” “will,” “should,” “future,” “propose”
and variations of these words or similar expressions (or the negative versions of such words or expressions) are intended to identify
forward-looking statements. These forward-looking statements are not guarantees of future performance, conditions or results, and involve
a number of known and unknown risks, uncertainties, assumptions and other important factors, many of which are outside Vivid Seats’
or Horizon’s control, that could cause actual results or outcomes to differ materially from those discussed in the forward-looking
statements. Important factors, among others, that may affect actual results or outcomes include the inability to complete the business
combination (including due to the failureof certain closing conditions); the inability to recognize the anticipated benefits of the proposed
business combination; the inability to obtain or maintain the listing of Vivid Seats’ shares on Nasdaq following the business combination;
costs related to the business combination; the risk that the business combination disrupts current plans and operations as a result of
the announcement and consummation of the business combination; Horizon and Vivid Seats’ ability to manage growth; Horizon and Vivid
Seats’ ability to execute its business plan and meet its projections; potential litigation involving Vivid Seats or Horizon; changes
in applicable laws or regulations, particularly with respect to gaming, and general economic and market conditions impacting demand for
Vivid Seats or Horizon products and services, and in particular economic and market conditions in the entertainment/technology/software
industry in the markets in which Vivid Seats and Horizon operate; and other risks and uncertainties indicated from time to time in the
proxy statement/prospectus relating to the business combination, including those under “Risk Factors” therein, and in Horizon’s
other filings with the SEC. None of Vivid Seats or Horizon undertakes any obligation to update or revise any forward-looking statements,
whether as a result of new information, future events or otherwise, except as required by law.
No Offer or Solicitation
This Current Report on Form 8-K does not constitute
a solicitation of a proxy, consent or authorization with respect to any securities or in respect of the proposed transaction. This Current
Report on Form 8-K also does not constitute an offer to sell or the solicitation of an offer to buy any securities, nor will there be
any sale of securities in any states or jurisdictions in which such offer, solicitation or sale would be unlawful prior to registration
or qualification under the securities laws of any such jurisdiction. No offering of securities will be made except by means of a prospectus
meeting the requirements of Section 10 of the Securities Act of 1933, as amended, or an exemption therefrom.