As far as exchange traded funds (ETFs) and exchange traded notes (ETNs) go, how lucrative was March madness? National Stock Exchange (NSX) announced that U.S.-listed ETF and ETN assets totaled $583 billion at the end of March 2008, a 28% increase from the end of March 2007, according to Mondovision.

Net cash inflow was $20.1 billion for the month of March. This finally reverses the trend of outflows seen in January and February, which lost $37.5 billion and $12.9 billion, respectively.

The number of ETFs in the United States has also grown by 48% in the last year. The current total is 703, up from 475 one year ago. And more ETF providers are entering the game: there are 30 now, up from 18 at this time in 2007.

These statistics include shares of open-ended ETF products, including listed shares of investment companies, grantor trusts, ETNs and commodity pools.

The opinions and forecasts expressed herein are solely those of Tom Lydon, and may not actually come to pass. Information on this site should not be used or construed as an offer to sell, a solicitation of an offer to buy, or a recommendation for any product.