The Utah Middle Market Business Index increased 11.46 percent in the last quarter of 1994, according to officials of First Security Bank of Utah and Arthur Andersen.

Kelly Matthews, First Security's chief economist, said the fourth-quarter index indicates significant solid growth among local middle market companies as they are "increasing revenues and creating more jobs in Utah."The index is an aggregate economic measurement of jobs and revenue growth among 29 public and privately held Utah companies. The 22.46 percent increase is a combination of a 6.09 percent increase in revenues in the fourth quarter over the same quarter a year and a 5.37 percent increase in the number of jobs over the last quarter of 1993.

According to the report released Tuesday during a media conference, "Revenues are up 6.09 percent, representing a pace about two times higher than the historical rate of inflation. Revenues are up by a robust 17.02 percent in the service segment, but revenues in the manufacturing, wholesale distribution and retail segments are relatively flat."

The report said jobs increased 5.37 percent in the past 12 months, which is 2,600 new jobs for Utah's middle-market companies. Jobs in the manufacturing segment increased 9.2 percent.

Based on results of the survey, Matthews said he expects Utah middle-market revenues to increase 7.9 percent in the next 12 months. "This is a rate 30 percent higher than the fourth-quarter 1994 increase over the fourth quarter of 1993," he said.

Matthews said the index companies' average productivity ratio (revenue per employee) increased 0.7 percent from $17,086 in the fourth quarter of 1993 to $17,202 in the fourth quarter of 1994.

He said a productivity increase of 10.3 percent in the service sector was diluted by a sizable decrease of 6.8 percent and 3.0 percent in the manufacturing and wholesale distribution segments, respectively.

The companies participating in the index are American Nutrition Inc.; ARUP Laboratories; Athletic Bag Co.; Bonneville News Co.; Brashers Auto Auction; EFI Electronics; Equity Oil Co.; Gull Laboratories; JB's Restaurants; Keystone Communications; Lagoon; Lifetime Products; Midwest Office Furniture & Supply; Monroc Inc.; and Moon Lake Electric Association.

Others are National Filter Media Corp.; Plumbers Supply Co.; Powder River Inc.; Premiums Oil Co.; Research Industries Corp.; Rocky Mountain Machinery; Scott Machinery Co.; SOS Temporaries; Sport Court Inc.; Titus Foods Inc.; Uinta Business Systems; Utah Medical Products Inc.; W.R. White Co.; and Young Electric Sign Co.