Alpha and Omega Semiconductor Joins Russell 3000 Index

June 29, 2010

SUNNYVALE, Calif., June 29, 2010 (GLOBE NEWSWIRE) -- Alpha and Omega Semiconductor Limited, or AOS (Nasdaq:AOSL), a designer, developer and global supplier of a broad range of power semiconductors, is pleased to announce that effective at the close of market on June 28, 2010, the Company's stock was added to the Russell 3000® Index as part of the annual reconstitution of the Russell indexes.

Annual reconstitution of Russell's U.S. indexes captures the 4,000 largest U.S. stocks as of the end of May, ranking them by total market capitalization. Membership in the Russell 3000, which remains in place for one year, means automatic inclusion in the large-cap Russell 1000® Index or small-cap Russell 2000® Index as well as the appropriate growth and value style indexes. Russell determines membership for its equity indexes primarily by objective, market-capitalization rankings and style attributes.

Dr. Mike F. Chang, AOS's Chairman, President and Chief Executive Officer, remarked, "AOS is very pleased to join the Russell 3000® Index. The inclusion reflects the success we have seen as we continue to execute our growth strategy. We believe our membership in the Russell Indexes will enhance our visibility with the investment community and represents another important milestone."

The Russell 3000 also serves as the U.S. component to the Russell Global Index, which Russell launched in 2007.

Russell indexes are widely used by investment managers and institutional investors for index funds and as benchmarks for both passive and active investment strategies. An industry-leading $3.9 trillion in assets currently are benchmarked to them. These investment tools originated from Russell's multi-manager investment business in the early 1980s when the Company saw the need for a more objective, market-driven set of benchmarks in order to evaluate outside investment managers.

Total returns data for the Russell 3000 and other Russell Indexes is available at http://www.russell.com/Indexes/data/default.asp

About Russell

Russell Investments provides strategic advice, world-class implementation, state-of-the-art performance benchmarks and a range of institutional-quality investment products. Russell has $179 billion in assets under management as of March 31, 2010, and serves individual, institutional and advisor clients in more than 40 countries. Founded in 1936, Russell is a subsidiary of The Northwestern Mutual Life Insurance Company.

About Alpha and Omega Semiconductor

Alpha and Omega Semiconductor Limited, or AOS, is a designer, developer and global supplier of a broad range of power semiconductors, including a wide portfolio of Power MOSFET and Power IC products. AOS seeks to differentiate itself by integrating its expertise in device physics, process technology, design and advanced packaging to optimize product performance and cost, and its product portfolio is designed to meet the ever increasing power efficiency requirements in high volume applications, including portable computers, flat panel TVs, battery packs, portable media players and power supplies.

Forward Looking Statements

This press release contains forward-looking statements that are based on current expectations, estimates, forecasts and projections of future performance based on management's judgment, beliefs, current trends and market conditions, and involve risks and uncertainties that may cause actual results to differ materially from those contained in the forward-looking statements. These factors include, but are not limited to, the ability to introduce and develop new products that achieve market acceptance, the ability to achieve design wins, the general business and economic conditions, the state of semiconductor industry, and other risks as described in the Company's filings with the Securities and Exchange Commission. Although the Company believes that the expectations reflected in the forward looking statements are reasonable, it cannot guarantee future results, level of activity, performance, or achievements. You should not place undue reliance on these forward-looking statements. All information provided in this press release is as of today's date, unless otherwise stated, and AOS undertakes no duty to update such information, except as required under applicable law.

CONTACT:  Alpha and Omega Semiconductor Limited
          Media Contact
          Clara Chan
          408.789.3233
          cchan@aosmd.com

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