Corporate Governance, Valuation, and Performance: Evidence from a Voluntary Market Reform in Brazil
研究了巴西圣保罗证券交易所2000年推出的自愿性公司治理改革，发现治理评分高的公司市场价值更高，但经营绩效并未更好，且基于治理评分构建的投资策略在2001-2005年间获得了年化10.68%的超额收益。
In December 2000, the São Paulo Stock Exchange launched a new premium market segment for companies that voluntarily commit to “good practices of corporate governance.” We construct a composite index (NM6) that combines six proxies for the main governance practices targeted by Bovespa's reform. We find that higher scores for our index are related to greater market value but not to better operating performance. An investment strategy that purchased stocks of firms with high NM6 and sold stocks of firms with low NM6 would have earned abnormal returns of 10.68% per year from 2001 to 2005.