Businesses need strong codes to protect themselves and their shareholders from political spending that is not in the companies' interest, according to a new report, as the 2008 race for the White House intensifies.

The study comes from the Center for Political Accountability, a non-profit organisiation that researches corporate political spending. The report found that although 81 of the S&P 100 already had codes governing political contributions, most of the corporate guidelines were non-specific, had insufficient transparency or failed to provide for oversight by corporate boards or top executives.