Rubicon Project Announces Intent to Convene, Adjourn and Reconvene in Virtual Meeting Format its Special Meeting of Stockholders to Be Held on March 30, 2020 Due To COVID-19 Concerns - Seite 2

As described in the joint proxy statement/prospectus for the special meeting previously distributed, Rubicon Project’s stockholders are entitled to participate in and vote at the special meeting if they were a stockholder of record as of the close of business on February 11, 2020, which is the record date for the special meeting, or hold an appropriate legal proxy for the meeting provided by their broker, bank or other nominee. Whether or not a stockholder plans to attend the reconvened special meeting by virtual means, Rubicon Project urges its stockholders to vote and submit their proxy in advance of the special meeting by one of the methods described in the joint proxy statement/prospectus. The proxy card included with the joint proxy statement/prospectus previously distributed will not be updated to reflect the information provided above and may continue to be used to vote each stockholder’s shares in connection with the special meeting. A prospectus supplement will be filed today with additional information concerning the virtual format of the reconvened special meeting, which we urge stockholders to read in its entirety. If Rubicon Project stockholders have previously submitted a proxy using one of the methods described in the joint proxy statement/prospectus and proxy card, their vote will be counted and they do not need to submit a new proxy or vote at the reconvened special meeting, although Rubicon Project stockholders may change or revoke their vote by attending the reconvened special meeting and voting virtually or by one of the other methods described in the joint proxy statement/prospectus.

About Rubicon Project

Founded in 2007, Rubicon Project is one of the world’s largest advertising exchanges. The company helps websites and apps thrive by giving them tools and expertise to sell ads easily and safely. In addition, the world’s leading agencies and brands rely on Rubicon Project’s technology to execute billions of advertising transactions each month. Rubicon Project is an independent, publicly traded company (NYSE:RUBI) headquartered in Los Angeles, California.

Additional Information and Where to Find It

On February 13, 2020, Rubicon Project filed with the U.S. Securities and Exchange Commission (“SEC”) a registration statement on Form S-4, which includes a joint proxy statement/prospectus. The joint proxy statement/prospectus contains important information about the proposed transaction and related matters. Investors and security holders of Rubicon Project and Telaria are urged to carefully read the entire joint proxy statement/prospectus (and any amendments thereto) and other filings made in connection therewith because such documents will contain important information about the proposed business combination. Rubicon Project and Telaria commenced the mailing of the joint proxy statement/prospectus to stockholders of Rubicon Project and Telaria on or about February 13, 2020.