PROXY STATEMENT/PROSPECTUS PROXY STATEMENT FOR EXTRAORDINARY GENERAL MEETING OF SHAREHOLDERS OF ION ACQUISITION CORP. 1 LTD. PROSPECTUS FOR UP TO 32,343,750 ORDINARY SHARES, AND 12,350,000 ORDINARY SHARES UNDERLYING WARRANTS OF TABOOLA.COM LTD. The board of directors of ION Acquisition Corp. 1 Ltd., a Cayman Islands exempted company (‘‘ION’’), has unanimously approved the agreement and plan of merger (‘‘Merger Agreement’’), dated as of January 25, 2021, by and among ION, Taboola.com Ltd., a company organized under the laws of the State of Israel (the ‘‘Company’’ or ‘‘Taboola’’), and Toronto Sub Ltd., a Cayman Islands exempted company and wholly owned subsidiary of the Company (‘‘Merger Sub’’). Pursuant to the Merger Agreement, Merger Sub will merge with and into ION, with ION surviving the merger (the ‘‘Business Combination’’). As a result of the Business Combination, and upon consummation of the Business Combination and the other transactions contemplated by the Merger Agreement (the ‘‘Transactions’’), ION will become a wholly owned subsidiary of Taboola, with the securityholders of ION becoming securityholders of Taboola. Pursuant to the Merger Agreement, at the effective time of the Business Combination (the ‘‘Effective Time’’), (a) each issued and outstanding unit of ION (an ‘‘ION Unit’’), consisting of one Class A ordinary share of ION, par value $0.0001 per share, of ION (‘‘Class A Ordinary Shares’’) and one-fifth of one warrant of ION entitling the holder to purchase one Class A Ordinary Share per warrant at a price of $11.50 per share (‘‘ION Warrants’’), will be automatically separated and the holder thereof will be deemed to hold one Class A Ordinary Share and one-fifth of one ION Warrant, (b) each Class A Ordinary Share outstanding immediately prior to the Effective Time will be exchanged for one ordinary share no par value per share of Taboola (‘‘Taboola Ordinary Shares’’), (c) each Class B ordinary shares, par value $0.0001 per share, of ION (‘‘Class B Ordinary Shares’’ and, together with Class A Ordinary Shares, ‘‘ION Ordinary Shares’’), outstanding immediately prior to the Effective Time, will be exchanged for one Taboola Ordinary Share and (d) each ION Warrant outstanding immediately prior to the Effective Time, will be assumed by Taboola and will become a warrant of Taboola (‘‘Taboola Warrants’’). Prior to the Effective Time, each outstanding Taboola convertible preferred share will be converted into Taboola Ordinary Shares in accordance with Taboola’s organizational documents and Taboola intends to effect a 1-for-2.7007 forward stock split to cause the value of the outstanding Taboola Ordinary Shares immediately prior to the Effective Time to equal $10.00 per share (the ‘‘Stock Split’’). Concurrently with and following the execution of the Merger Agreement, Taboola and certain accredited investors (‘‘PIPE Investors’’) entered into a series of subscription agreements (‘‘Subscription Agreements’’), providing for the purchase by the PIPE Investors at the Effective Time of an aggregate of 13,500,000 Taboola Ordinary Shares (‘‘PIPE Shares’’) at a price per share of $10.00 (assuming the Stock Split has been effected), for gross proceeds to Taboola of $135,000,000 (collectively, the ‘‘PIPE’’). The closing of the PIPE is conditioned upon the consummation of the Transactions. Concurrently with and following the execution of the Merger Agreement, Taboola and certain accredited investors (the ‘‘Secondary Investors’’) entered into share purchase agreements with certain shareholders of Taboola (the ‘‘Secondary Share Purchase Agreements’’) pursuant which the Secondary Investors committed to purchase Taboola Ordinary Shares from certain shareholders of Taboola, and, under certain circumstances, from Taboola, an aggregate of up to 15,120,000 Taboola Ordinary Shares (the ‘‘Secondary Shares’’) at a price per share of $10.00 (assuming the Stock Split has been effected), for gross proceeds up to of $151,200,000 (the ‘‘Secondary Purchases’’). This proxy statement/prospectus covers the Taboola Ordinary Shares issuable to the securityholders of ION as described above. Accordingly, we are registering up to an aggregate of 32,343,750 Taboola Ordinary Shares and 12,350,000 Taboola Ordinary Shares issuable upon the exercise of the Taboola Warrants. We are not registering the Taboola Ordinary Shares held by or issuable to Taboola securityholders or the PIPE Investors. Proposals to approve the Merger Agreement and the other matters discussed in this proxy statement/prospectus will be presented at the extraordinary general meeting of ION shareholders scheduled to be held on June 28, 2021, in virtual format. Although Taboola is not currently a public reporting company, following the effectiveness of the registration statement of which this proxy statement/prospectus is a part and the closing of the Business Combination, Taboola will become subject to the reporting requirements of the Securities Exchange Act of 1934, as amended (the ‘‘Exchange Act’’). Taboola intends to apply for listing of the Taboola Ordinary Shares and Taboola Warrants on the Nasdaq Global Market (‘‘Nasdaq’’) under the proposed symbols ‘‘TBLA’’ and ‘‘TBLAW,’’ respectively, to be effective at the consummation of the Business Combination. It is a condition of the consummation of the Transactions that the Taboola Ordinary Shares are approved for listing on Nasdaq (subject only to official notice of issuance thereof and round lot holder requirements). While trading on Nasdaq is expected to begin on the first business day following the date of completion of the Business Combination, there can be no assurance that Taboola’s securities will be listed on Nasdaq or that a viable and active trading market will develop. See ‘‘Risk Factors’’ beginning on page 17 for more information. Taboola will also be a ‘‘foreign private issuer’’ as defined in the Exchange Act and will be exempt from certain rules under the Exchange Act that impose certain disclosure obligations and procedural requirements for proxy solicitations under Section 14 of the Exchange Act. In addition, Taboola’s officers, directors and principal shareholders will be exempt from the reporting and ‘‘short-swing’’ profit recovery provisions under Section 16 of the Exchange Act. Moreover, Taboola will not be required to file periodic reports and financial statements with the U.S. Securities and Exchange Commission as frequently or as promptly as U.S. companies whose securities are registered under the Exchange Act. The accompanying proxy statement/prospectus provides ION shareholders with detailed information about the Business Combination and other matters to be considered at the extraordinary general meeting of ION. We encourage you to read the entire accompanying proxy statement/prospectus, including the Annexes and other documents referred to therein, carefully and in their entirety. You should also carefully consider the risk factors described in ‘‘Risk Factors’’ beginning on page 17 of the accompanying proxy statement/prospectus. None of the Securities and Exchange Commission, any state securities commission or the Israel Securities Authority has approved or disapproved of the securities to be issued in connection with the Business Combination, or determined if this proxy statement/prospectus is accurate or adequate. Any representation to the contrary is a criminal offense. This proxy statement/prospectus is dated June 8, 2021, and is first being mailed to ION shareholders on or about June 8, 2021. ION ACQUISITION CORP 1 LTD. 89 Medinat Hayehudim Street Herzliya 4676672, Israel NOTICE OF EXTRAORDINARY GENERAL MEETING TO BE HELD ON JUNE 28, 2021 TO THE SHAREHOLDERS OF ION ACQUISITION CORP 1 LTD. NOTICE IS HEREBY GIVEN that an extraordinary general meeting (the ‘‘meeting’’) of ION Acquisition Corp 1 Ltd., a Cayman Islands exempted company (‘‘ION’’), will be held at 11:00 a.m. Eastern time, on June 28, 2021, at https://www.cstproxy.com/ionacquisitioncorp1/sm2021. In light of ongoing developments related to the coronavirus (COVID-19) pandemic, after careful consideration, ION has determined that the meeting will be a virtual meeting conducted via live webcast in order to facilitate shareholder attendance and participation while safeguarding the health and safety of our shareholders, directors and management team. For the purposes of Cayman Islands law and the amended and restated memorandum and articles of association of ION (the ‘‘ION Articles’’), the physical location of the meeting shall be at the offices of White & Case LLP at 1221 Avenue of the Americas, New York, New York 10020. You or your proxyholder will be able to attend and vote at the meeting online by visiting https://www.cstproxy.com/ionacquisitioncorp1/sm2021 and using a control number assigned by Continental Stock Transfer & Trust Company, the transfer agent to ION. To register and receive access to the hybrid virtual meeting, registered shareholders and beneficial shareholders (those holding shares through a stock brokerage account or by a bank or other holder of record) will need to follow the instructions applicable to them provided in the attached proxy statement/prospectus of which this notice forms a part. You are cordially invited to attend the meeting, in order to consider and vote on proposals to: (1) Proposal No. 1 — The Business Combination Proposal — An Ordinary Resolution to approve, ratify and adopt the Merger Agreement, dated as of January 25, 2021 (as it may be amended and/or restated from time to time, the ‘‘Merger Agreement’’ and to which the form of Plan of Merger required by the Companies Act (as amended) of the Cayman Islands (the ‘‘Plan of Merger’’) is appended) by and among ION, Taboola.com Ltd. (‘‘Taboola’’) and Toronto Sub Ltd. (‘‘Merger Sub’’), a copy of which is attached to the proxy statement as Annex A, and approve the transactions contemplated thereby (the ‘‘Business Combination’’); and (2) Proposal No. 2 — The Merger Proposal — A Special Resolution to approve the Plan of Merger and to authorize the merger of Merger Sub with and into ION, with ION surviving the merger as a wholly owned subsidiary of Taboola, and the issuance of ordinary shares of Taboola to ION shareholders as merger consideration; and (3) Proposal No.