本文針對銀行業的業務分散程度與績效的關係，做實證上的研究。以一九九五年至二零零四年之間全球金融機構為研究對象，實證結果發現，業務較集中的金融機構會比業務較分散者的績效來得好，而且隨著分散的程度提高，績效變差的情況會更為明顯。除此之外，當銀行的本業是非利息收入時，提高業務分散程度所造成的績效降低會比本業為放款的銀行更為明顯。實證結果同時也指出，政府機關與民間的監督機制都能夠有助於減輕此種業務分散帶來的績效下降。 / This study examines the relationship between diversification of financial activities and performance in banking industry. Using cross-country data of financial institutions from 1995 to 2004, the empirical results suggest that focused banks outperform diversified banks. Moreover, I find that diversification discount declines as banks go diversified. Results show that banks which focus previously on noninterest income would suffer heavier diversification discount than loan-specialized banks while extending their activity into the other area. Results also suggest that the supervisory power from regulatory authorities and the policy of private-sector monitoring can help alleviate diversification discount that banks would experience when they go diversified.