instruction: Tell me about the merger history of the Swiss bank UBS
context: Swiss Bank Corporation was a Swiss investment bank and financial services company located in Switzerland. Prior to its merger, the bank was the third largest in Switzerland with over CHF 300 billion of assets and CHF 11.7 billion of equity.
  
  Throughout the 1990s, SBC engaged in a large growth initiative, shifting its focus from traditional commercial banking into investment banking, in an effort to match its larger Swiss rival Credit Suisse. As part of this strategy, SBC acquired US-based investment bank Dillon Read & Co. as well as London-based merchant bank S.G. Warburg in the mid-1990s. SBC also acquired Chicago-based Brinson Partners and O'Connor & Associates. These acquisitions formed the basis for a global investment banking business.
  
  In 1998, SBC merged with Union Bank of Switzerland to form UBS, the largest bank in Europe and the second largest bank in the world. The company's logo, which featured three keys, symbolizing "confidence, security, and discretion", was adopted by UBS after the 1998 merger. Although the combination of the two banks was billed as a merger of equals, it quickly became evident that from a management perspective, it was SBC that was buying UBS as nearly 80% of the top management positions were filled by legacy Swiss Bank professionals. Today, what was SBC forms the core of many of UBS's businesses, particularly UBS Investment Bank.
response: The Swiss Bank Corporation was a Swiss investment bank and financial services company located in Switzerland. Prior to its merger, the bank was the third largest in Switzerland with over CHF 300 billion of assets and CHF 11.7 billion of equity.
  
  Throughout the 1990s, SBC engaged in a large growth initiative, shifting its focus from traditional commercial banking into investment banking, in an effort to match its larger Swiss rival Credit Suisse. As part of this strategy, SBC acquired US-based investment bank Dillon Read & Co. as well as London-based merchant bank S.G. Warburg in the mid-1990s. SBC also acquired Chicago-based Brinson Partners and O'Connor & Associates. These acquisitions formed the basis for a global investment banking business.
  
  In 1998, SBC merged with Union Bank of Switzerland to form UBS, the largest bank in Europe and the second largest bank in the world. The company's logo, which featured three keys, symbolizing "confidence, security, and discretion", was adopted by UBS after the 1998 merger. Although the combination of the two banks was billed as a merger of equals, it quickly became evident that from a management perspective, it was SBC that was buying UBS as nearly 80% of the top management positions were filled by legacy Swiss Bank professionals. Today, what was SBC forms the core of many of UBS's businesses, particularly UBS Investment Bank.