ZURICH--U.S. assets offer a better risk-return profile than European securities, Alexander Friedman, chief investment officer at UBS AG (UBS), said Thursday. "With the economic and political outlooks still favouring the U.S., we believe it continues to make sense to prefer U.S. assets over European assets," Mr. Friedman said in a monthly letter to clients. As a result, Switzerland's largest bank by assets, prefers the dollar over the euro, U.S. equities over euro-zone stocks and U.S. corporate bonds over debt issues from European companies. "U.S. companies issuing in the high-yield market remain cash rich, and we believe that default rates will remain low while the economy is still growing," he said. Write to anita.greil@dowjones.com Subscribe to WSJ: http://online.wsj.com?mod=djnwires