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 jeopardising jobs.

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

Siegel said he was not ordering his employees to vote his way. “There’s no way I can pressure anybody,” he said. “I’m not in the voting booth with them.” Siegel added: “I really wanted them to know how I felt four more years under President Obama was going to affect them.”

Dave Robertson, president of Koch Industries, sent an information packet and letter this month to more than 30,000 employees of a subsidiary, Georgia-Pacific, a paper and pulp company. The letter attacked government subsidies for “a few favored cronies” as well as “unprecedented regulatory burdens on businesses.”

The letter added, “Many of our more than 50,000 US employees and contractors may suffer the consequences, including higher gasoline prices, runaway inflation and other ills.”

The Georgia-Pacific letter, first reported by In These Times, included a flier listing several candidates endorsed by the Koch brothers, the conservative billionaires, beginning with Mitt Romney, as well as opinion articles that the brothers had written. In a statement, Koch Industries said its mailing contained pieces of information “we believe are important for our employees to know about.” The company said the letter was in no way intimidation.

Other companies whose top executives have sent out anti-Obama letters include Rite-Hite, an industrial equipment manufacturer in Milwaukee, and Naples-based ASG Software Solutions.

Bradley A Smith, a Republican former member of the Federal Election Commission and a professor at Capital University Law School said letters like those sent by the companies were not firm threats to fire anyone if Obama won.