Burbank-based Shamrock Holdings Inc., said it has...

Burbank-based Shamrock Holdings Inc., said it has completed purchase of Music Plus, a 56-store Los Angeles chain of record and home-entertainment stores . . . The Federal Reserve said the average yield for one-year T-bills, the most popular index for making changes in adjustable rate mortgages, was 7.79% last week, unchanged from the week before.