NEW YORK, June 10, 2013 (GLOBE NEWSWIRE) -- The NASDAQ OMX Group, Inc. (Nasdaq:NDAQ) today announced changes to the methodology of the NASDAQ Biotechnology Index ® (Nasdaq:NBI). The NASDAQ Biotechnology Index, which is designed to track the performance of a set of NASDAQ listed securities classified as either biotechnology or pharmaceutical according to the Industry Classification Benchmark (ICB), will continue to employ a modified market capitalization weighting; however, the rebalancing procedures will change. Going forward, the Index will be rebalanced each quarter, to ensure the maximum weight of any Index security does not exceed 8 percent, and no more than five securities are at that cap. For a complete description of the revised Index methodology, please visit https://indexes.nasdaqomx.com/docs/methodology_NBI.pdf . Due to considerable growth in the biotechnology sector, particularly in the last six months, NASDAQ OMX has decided to modify the methodology to ensure the Index Securities are closer in line with their actual market capitalizations. The decision reflects NASDAQ OMX's commitment to ensure the NASDAQ Biotechnology Index remains one of the most widely-followed biotechnology benchmarks in the world. In addition, the Index will change to an annual evaluation in December. Previously, the index was changed on a semi-annual basis. The new rebalancing procedures used to calculate Index shares will become effective after the close of trading on Friday, June 21, 2013. Additions and deletions of securities will be made after the close of trading on the third Friday in December. For more information about the NASDAQ Biotechnology Index, including detailed eligibility criteria, and complete methodology, visit https://indexes.nasdaqomx.com/ . The NASDAQ Biotechnology Index is the basis for the iShares NASDAQ Biotechnology Index SM Fund (Nasdaq:IBB), the ProShares Ultra NASDAQ Biotechnology ETF (Nasdaq:BIB) and the ProShares UltraShort NASDAQ Biotechnology ETF (Nasdaq:BIS). For more information about these funds, visit https://indexes.nasdaqomx.com/Index/Overview/NBI . About NASDAQ OMX Global Indexes NASDAQ OMX Global Indexes has been creating innovative, market-leading, transparent indexes since 1971. Today, our index offering spans geographies and asset classes and includes diverse families such as the Dividend Achievers, Global, Nordic, Green Economy, Sharia and Commodity Indexes. We continuously offer new opportunities for financial product sponsors across a wide-spectrum of investable products and for asset managers to measure risk and performance. NASDAQ OMX Global Indexes also provides custom index services and design solutions to selected financial organizations. For more information about NASDAQ OMX Global Indexes, visit indexes.nasdaqomx.com. Daily index values, weightings and historical data for NASDAQ OMX indexes are available via NASDAQ OMX Global Index Watch and NASDAQ OMX Global Index Data Service. About NASDAQ OMX Group The inventor of the electronic exchange, The NASDAQ OMX Group, Inc., fuels economies and provides transformative technologies for the entire lifecycle of a trade - from risk management to trade to surveillance to clearing. In the U.S. and Europe, we own and operate 23 markets, 3 clearinghouses and 5 central securities depositories supporting equities, options, fixed income, derivatives, commodities, futures and structured products. Able to process more than 1 million messages per second at sub-40 microsecond speeds with 99.99+% uptime, our technology drives more than 70 marketplaces in 50 developed and emerging countries into the future, powering 1 in 10 of the world's securities transactions. Our award-winning data products and worldwide indexes are the benchmarks in the financial industry. Home to over 3,300 listed companies worth more than $6 trillion in market cap whose innovations shape our world, we give the ideas of tomorrow access to capital today. Welcome to where the world takes a big leap forward, daily. Welcome to the NASDAQ OMX Century. To learn more, visit www.nasdaqomx.com. Follow us on Facebook ( www.facebook.com/NASDAQ) and Twitter ( www.twitter.com/nasdaqomx). (Symbol: NDAQ and member of S&P 500) The Industry Classification Benchmark ("ICB") is owned by FTSE International Limited and has been licensed for use. "FTSE™" is a trade mark of London Stock Exchange Group companies and is used by FTSE under licence. FTSE does not accept liability to any person for any loss or damage arising out of any error or omission in the ICB.