ETF fund assets and numbers continue to soar in 2008. As of May 31, there were 683 ETFs in the U.S., with assets totaling approximately $612 billion. ETF industry assets rose nearly $17 billion for the month of May, buoyed by positive performance in the global equity markets, while some 23 new ETFs were launched during the month. Year-to-date, inverse/leveraged ETFs saw the biggest percent increase in assets, up 88 percent through May 31 to $8.5 billion. Currency and specialty ETFs followed, with assets up 42 percent and 40 percent, respectively, to $1.5 billion and $3.0 billion. But the category with the greatest total assets is international, at $166 billion. The ETF industry's offerings are still highly concentrated in the hands of a few ETF managers, especially when it comes to the domestic market: BGI, State Street and Vanguard account for approximately 85 percent of the ETFs listed domestically.