The vast majority of U.S. companies are making multiple adjustments in their pay programs for executives and other employees in response to the deepening economic crisis, according a new Towers Perrin survey.

Overall, the modifications will mean lower – or no – 2009 salary increases and bonuses for 2008 performance for many U.S. employees, along with reductions in the value of 2009 equity grants for many executives.

The survey was conducted by the Stamford, Conn.-based company online from Jan. 6 – 14, and targeted U.S.-based midsize and large companies. A total of 513 companies participated in the survey, which provides the most current insights into how U.S. businesses are planning to address workforce and compensation issues in light of ongoing economic uncertainty. The survey was also conducted in Asia, Europe and the Americas with a total of over 1,150 responses. This study updates an earlier online survey conducted by Towers Perrin in October.

The survey also shows that many companies are rethinking their approach to determining the size of their 2009 long-term incentive grants in light of significant stock price declines and considering what to do, if anything, about underwater stock options.