UBS opened branches and acquired a series of banks in Switzerland in the following years, growing from 31 offices in 1950 to 81 offices by the early 1960s.[71] In 1960, Union Bank of Switzerland acquired an 80% stake in Argor SA, a Swiss precious metals refinery founded in 1951 in the canton of Ticino.[2] UBS continues to issue gold bars via Argor-Heraeus which is famous for the unique kinebar holographic technology it uses to provide enhanced protection against bank gold bar counterfeiting.[95] By 1962, Union Bank of Switzerland reached CHF 6.96 billion of assets, narrowly edging ahead of Swiss Bank Corporation to become the largest bank in Switzerland.[96] The rapid growth was punctuated by the 1967 acquisition of Interhandel, which made UBS one of the strongest banks in Europe.[5]