Westport to Ring NASDAQ Closing Bell and Holds Investor Day in New York May 24th

Natural Gas-powered Ford F-250 Displayed in Times Square; Presentations and Video Available on Westport Website Following Event

Westport Closes Offering of Common Shares and Announces Underwriters' Exercise of Over-Allotment Option

Westport announces the closing of its previously announced offering of common shares in the United States and Canada, including the exercise in full of the underwriters' option to purchase an additional 825,000 common shares at the offering price of US$43.25 per share. With the exercise of the option, Westport issued a total of 6,325,000 common shares under the offering for gross proceeds of US$273,556,250.

Westport Innovations Inc. Prices Offering of Common Shares

Westport announced the pricing of its offering of common shares in the United States and Canada. Westport will offer 5,500,000 common shares at a price of US$43.25 per share, for gross proceeds of US$237,875,000. Westport has granted the underwriters of the offering an option to purchase an additional 825,000 common shares at the offering price during the period ending 30 days from the date of Westport's final prospectus supplement filed in connection with the offering to cover over-allotments, if any. If the over-allotment option is exercised in full, gross proceeds of the offering will be US$273,556,250.

Westport Innovations Inc. Offers Common Shares

Westport is offering to sell, subject to market and other conditions, 5,000,000 of its common shares in the United States and Canada pursuant to a preliminary prospectus supplement to its base shelf prospectus originally dated January 3, 2012. Copies of the U.S. preliminary prospectus supplement can be accessed through the SEC's website at www.sec.gov, and copies of the Canadian preliminary prospectus supplement are available at www.sedar.com.

Westport Innovations to Ring NASDAQ Opening Bell

Natural Gas Truck on Display in Times Square

Westport announced it will ring the Opening Bell of the NASDAQ Stock Market on Tuesday, May 31, 2011 at 9:30 am (Eastern Time) at NASDAQ MarketSite in New York. In honour of the event, Westport’s management team and several members of the Board of Directors will be in attendance to ring the bell. At the same time, a natural gas truck powered by a Cummins Westport ISL G engine will be on display outside NASDAQ MarketSite in Times Square.

Westport Announces Agreement with Caterpillar for Evaluation of Fuel System Technologies for High Horsepower Engines

Westport is in an agreement with Caterpillar, Inc. to evaluate direct injection, natural gas fuel system technologies for possible use on Caterpillar’s large engines. As part of the agreement, the parties will combine their respective technologies and components to develop a fuel system that will be evaluated on a multi-cylinder test engine.

Westport Commences Trading on Nasdaq

Westport has commenced trading on the Nasdaq Global Market under the symbol “WPRT” and is now dual listed on both the Toronto Stock Exchange (under the symbol “WPT”) and the Nasdaq.

Westport Innovations Inc. Files U.S. IPO Registration Statement with SEC in Connection with NASDAQ Listing Application and Effects Share Consolidation

Westport has filed a registration statement on Form F-10 with the U.S. Securities and Exchange Commission concurrently with a short-form prospectus in Canada in connection with its planned initial public offering of common shares in the United States. The common shares are being concurrently offered in Canada under the short-form prospectus.