Imagine getting a letter from the boss, telling you how to vote.

Until 2010, federal law barred companies from using corporate money to endorse and campaign for political candidates — and that included urging employees to support specific politicians.

But the Supreme Court’s Citizens United decision has freed companies from those restrictions, and now several major companies, including Georgia-Pacific and Cintas, have sent letters or information packets to their employees suggesting — and sometimes explicitly recommending — how they should vote this fall.

In these letters, the executives complain about the costs of overregulation, the health care overhaul and possible tax increases. Some letters warn that if President Obama is re-elected, the company could be harmed, potentially jeopardizing jobs.

David A. Siegel, 77, chief executive of Westgate Resorts, a major time-share company, wrote to his 7,000 employees, saying that if Mr. Obama won, the prospect of higher taxes could hurt the company’s future.