TSC Ratings provides exclusive stock, ETF and mutual fund ratings and commentary based on award-winning, proprietary tools. Its "safety first" approach to investing aims to reduce risk while seeking solid outperformance on a total return basis.Barclays ( BCS) dominates the list of the 25 best-rated exchange-traded funds on the strength of its fixed-income funds during the longest recession in more than half a century. Twenty-one of the 25 most highly rated ETFs are owned by Barclays or track a Barclays index. Barclays agreed to sell its iShares ETFs to CVC Capital Partners for $4.4 billion. The pending sale is bullish for Barclays in that the deal locks in a fair price while allowing the company to continue to shop iShares to other potential suitors until the acquisition closes. Also, if CVC successfully resells iShares, Barclays gets 20% of the increase in cash. Barclays retains the revenue generated from the securities servicing for iShares, although State Street ( STT) and Bank of New York Mellon ( BK) have been cited as potential bidders on this business. The three best-rated exchange-traded funds based on March 31 data are Market Vectors-Barclays AMT-Free Short Municipal ETF ( SMB), SPDR Barclays Capital Short Term Municipal Bond ETF ( SHM) and the iShares Barclays 10-20 Year Treasury Bond Fund ( TLH). In this time of financial uncertainty, the "buy"-rated fixed income ETFs listed below can be used to balance the overall risk in an investor's portfolio. The only two non-fixed-income ETFs with top grades on the list are bullish currency plays. The PowerShares DB US Dollar Index Bullish Fund ( UUP) is a bet on the U.S. dollar against the euro, Japanese yen, British pound, Canadian dollar, Swedish krona and Swiss franc. The Market Vectors-Renminbi/USD ETN ( CNY) uses short-term forward contracts to benefit from a rise in China's currency in relation to the U.S. dollar.