With prominent business leaders and politicians accused of wrongdoing during the past year, investors have grown much more mistrustful, according to a survey sponsored by financial services company TIAA-CREF.

The survey is used to develop the Trust in America Index, which measures investors’ trust in a range of people and institutions. The index fell sharply to 10.8 percent from 13.2 percent a year ago. It’s based on the average number of people who consider each type of person or institution very trustworthy.

“Continuing headlines about corporate scandals as well as the situation in Iraq have driven investor trust from low to lower in the past year,” said Glen Weiner, a polling director at TIAA-CREF. “The drop in trust has had an impact on investor behavior as well – making them more conservative with their investments.”

The September telephone survey involved 1,001 people older than 30 with investment products.