US companies have faced a blizzard of new corporate governance laws and regulations in the past two years but real reform is yet to come, according to a prominent US shareholder activist.

Ralph Whitworth, principal of Relational Investors, a $2.4bn (€2.1m) activist fund, said the Sarbanes-Oxley act was of far less significance than the recent proposal by the Securities and Exchange Commission (SEC) to give investors the ability to nominate directors.