The nation’s largest public pension fund, the California Public Employees’ Retirement System, recently fired off a letter to the Fortune 100 CEOs, asking them to disclose any “interested-party transactions.” Specifically, the fund wants the CEOs to provide information on directors and executives who hold a financial interest in companies with which the CEOs do business. CalPERS is also wants to know which directors and officers hold an interest in companies acquired by the CEOs.