Zions Investment Securities Inc. on Monday became the first  national bank subsidiary to underwrite a municipal revenue bond offering. 
The Salt Lake City-based company, which is a unit of Zions First  National Bank, raised $4.2 million for Summit County, Utah. 
  
The bank was the first to take advantage of the Comptroller of the  Currency's controversial "op-sub" rule, which lets national bank   subsidiaries engage in activities that the parent may not perform directly.   The securities unit was formed in December.     
W. David Hemingway, executive vice president at Zions Investment  Securities, said he wants to serve towns ignored by most investment firms.   "We believe we can save small communities substantial amounts of money," he   said.     
  
Monday's offering provided funds for a 15,000-square-foot addition to  Summit County's office in Coalville. The revenue bonds pay 4.51% a year and   mature in 2013. -Bill McConnell