The Bloomberg Business Week magazine published an article about the serious flaws of commodity exchange-traded funds. Investors have sometimes lost money even when commodity prices were rising. In fact, many of these ETFs invest in commodity futures rather than in actual physical commodities. The differential between futures and spot prices sometimes lead these ETFs to recurring losses. Futhermore, the article claims that some institutions have organized themselves to take advantage of these flaws at the expense of commodity ETF investors.