INDIANAPOLIS, April 23, 2012 /PRNewswire/ -- Allison Transmission Holdings, Inc. (NYSE: ALSN), the world's largest manufacturer of commercial duty fully-automatic transmissions and hybrid-propulsion systems, announced today that it was added to the Wilshire 5000 Total Market Index(SM) (Wilshire 5000(SM)) effective after the markets' close on Friday, April 20, 2012. "We are very pleased to be part of the Wilshire 5000(SM), " stated Lawrence E. Dewey, Chairman, President and Chief Executive Officer of Allison Transmission. "The inclusion of Allison Transmission in the Wilshire 5000 Index follows the company's successful initial public offering and our recently issued strong first quarter 2012 financial results. The addition of our company to the Index will provide an opportunity to further broaden our shareholder base and potentially create additional value for our existing shareholders." The Wilshire 5000, the original pure and complete(SM) measure of the U.S. stock market, was developed in 1974 by Dennis A. Tito, chairman and chief executive officer of Wilshire Associates Incorporated. It is widely considered the best way to track the U.S. equities market and estimate market value changes. The Wilshire 5000 Total Market exchange-traded fund (NYSE Arca: WFVK) is the only ETF based upon the Wilshire 5000. About Allison Transmission Allison Transmission is the world's largest manufacturer of fully-automatic transmissions for medium- and heavy-duty commercial vehicles, medium- and heavy-tactical U.S. military vehicles and hybrid-propulsion systems for transit buses. Allison transmissions are used in a variety of applications including on-highway trucks (distribution, refuse, construction, fire and emergency), buses (primarily school and transit), motor homes, off-highway vehicles and equipment (primarily energy and mining) and military vehicles (wheeled and tracked). Founded in 1915, the Allison business is headquartered in Indianapolis, Indiana, U.S.A. and employs approximately 2,800 people. Allison has manufacturing facilities and customization centers located in China, The Netherlands, Brazil, India and Hungary, with a global presence, serving customers in North America, Europe, Asia, Australia, South America and Africa. Allison also has more than 1,500 independent distributor and dealer locations worldwide. More information about Allison is available at www.allisontransmission.com.