Investors are nervous about California’s ballot initiative Proposition 23, which would overturn the state’s landmark Global Warming Solutions Act of 2006 or AB 32. Last week, 23 investors announced that they filed shareholder resolutions with oil companies Occidental Petroleum, Valero Energy Corp. and Tesoro Corp. All three of the oil companies have funded Proposition 23. The shareholder resolutions request Board reviews and oversight of the companies’ political contributions and policies...Laura Campos, Director of Shareholder Activities at the Nathan Cummings Foundation, said that shareholders are “concerned Tesoro’s support for the highly controversial Proposition 23 could lead to a decrease in shareholder value by damaging the company’s reputation and negatively impacting the business environment in a state where Tesoro has significant operations.”