ByJohn S. McClenahen Like several other recent measures of economic confidence, the UBS Index of Investor Optimism has fallen significantly since January. The index, compiled by UBS Investment Research, New York, slid to a five-month low of 85 this month, compared with 97 in February and 108 in January. Investor issues influencing its fall: accounting practices, the federal budget deficit, outsourcing and higher energy prices, says UBS. "However, these concerns did not reduce the median expected 12-month investment returns, which remained at 8%," UBS notes. And the March index remained close to its 89 average for the final three months of 2003, says UBS. "The message, thus, appears to be more that confidence is consolidating than it is collapsing."