Anheuser-Busch gave him six figures, Colgate-Palmolive shelled out $50,000 and Macy’s and Pfizer have contributed thousands to the Rev. Al Sharpton’s charity.

Almost 50 companies – including PepsiCo, General Motors, Wal-Mart, FedEx, Continental Airlines, Johnson & Johnson and Chase – and some labor unions sponsored Sharpton’s National Action Network annual conference in April.

Terrified of negative publicity, fearful of a consumer boycott or eager to make nice with the civil-rights activist, CEOs write checks, critics say, to NAN and Sharpton – who brandishes the buying power of African-American consumers. In some cases, they hire him as a consultant.

The cash flows even as the US Attorney’s Office in Brooklyn has been conducting a grand-jury investigation of NAN’s finances.

A General Motors spokesman told The Post that NAN had repeatedly – and unsuccessfully – asked for contributions for six years, beginning in August 2000.

Then, in December 2006, Sharpton threatened to call a boycott of the carmaker over the closing of an African-American-owned GM dealership in The Bronx, and he picketed outside GM headquarters on Fifth Avenue.

Last year, General Motors gave NAN a $5,000 donation. It gave $5,000 more this year, a spokesman said, calling NAN a “worthy” organization.

In November 2003, Sharpton picketed DaimlerChrysler’s Chicago car show and threatened a boycott over alleged racial bias in car loans.

“This is institutional racism,” he bellowed.

In May 2004, Chrysler began supporting NAN’s conferences, which include panels on corporate responsibility and civil rights and a black-tie awards dinner to honor Martin Luther King Jr. Last year, Sharpton gave Chrysler an award for corporate excellence.

In 2003, Sharpton targeted American Honda for not hiring enough African-Americans in management.

“We support those that support us,” wrote Sharpton and the Rev. Horace Sheffield III, president of NAN’s Michigan chapter, in a letter to American Honda. “We cannot be silent while African-Americans spend hard-earned dollars with a company that does not hire, promote or do business with us in a statistically significant manner.”

Two months after American Honda execs met with Sharpton, the carmaker began to sponsor NAN’s events – and continues to pay “a modest amount” each year, a spokesman said.

“I think this is quite clearly a shakedown operation,” said Peter Flaherty, president of the National Legal and Policy Center in Virginia, a conservative corporate watchdog. “He’s good at harassing people and making noise. CEOs give him his way because it is a lot easier than confronting him.”

Sharpton denies his organization pressures corporations for cash.

“That’s the old shakedown theory that the anti-civil-rights forces have used against us forever,” he told The Post yesterday. “Why can’t they come up with one company that says that? No one has criticized me.”

A businessman who hired Sharpton as a consultant says the flamboyant leader skillfully persuades CEOs by wielding the statistic that African-Americans spend $738 billion a year.

“His way of doing things was, ‘If we’re going to support you and you’re not going to support us, then we have to focus on telling the African-American community not to spend their money,’ ” said La-Van Hawkins, a partner in Hawkins Food Group, which owns and operates fast-food franchises nationwide.

Hawkins spoke from the Yankton Federal Prison in South Dakota, where he’s serving time for attempted bribery.

After Hawkins lost an attempt to sue Burger King in 2000 for denying him franchises, he sent Sharpton, attorney Johnnie Cochran and a Miami lawyer to meet with the company’s top execs.

“They ended up settling with me for $31 million,” Hawkins said.

Sharpton did not get a cut, but Hawkins Food Group paid him an annual $25,000 fee, Hawkins said. He said he has donated “over $1 million” to NAN.

Sharpton has snagged other gigs as a consultant. Less than a year after he threatened to call for a consumer boycott of Pepsi in June 1998 because the company’s ads did not portray African-Americans, the company hired him as a $25,000-a-year adviser until 2007.

Sharpton made the same complaint against Macy’s in 1998. The company appointed Sharpton an unpaid adviser on diversity, but also funds NAN’s annual conference. Last week, Macy’s Senior Vice President Ed Goldberg praised Sharpton as “the kind of guy you can sit down and talk to.”

In a dramatic flip-flop, Sharpton in 2000 blasted New York developer Bruce Ratner for paying low wages to workers at his Atlantic Mall in Brooklyn.

“We will not allow you to enslave our communities, Mr. Ratner,” Sharpton told a rally. “You must meet with us – you must come to terms with the poverty you are creating using public dollars.”

By 2004, the developer’s company, Forest City Ratner, had begun to fork over thousands of dollars to NAN. Sharpton now strongly supports Ratner’s proposed Atlantic Yards project, which includes a new arena for the New Jersey Nets.

“Just because Pepsi and other companies had me on their board advising them didn’t mean that I wasn’t blasting them all the time,” said Sharpton.

“Look at Forest City Ratner. I blasted them and they came up with one of the best community agreements for blacks and Latinos.”

NAN, which began humbly in Harlem in 1991 with Saturday-morning rallies at PS 175, now boasts 45 chapters across the country. The group lobbies for African-American rights and raises awareness of issues such as police brutality and racial profiling.

“Sharpton went national just like a franchise,” said Flaherty. “Each of these local chapters can now hit up businesses for support in their communities.”

In 2002, NAN launched a Las Vegas chapter that solicits corporate and individual donations of up to $5,000 on its Web site. NAN spokesman Charlie King said all donations go through the New York office.

It’s unclear how much the chapter has raised, because Nevada does not require charities to report their revenues. King would not give numbers.

Sharpton vowed to call a national boycott against MGM Mirage in 2001 and 2002 if it refused to meet with him to discuss alleged racism in hiring and employment at the company’s Detroit casino.

In 2003, MGM named NAN one of its diversity “partners” in Detroit.

Sharpton sticks up for his corporate patrons.

Since 2005, Wal-Mart has given yearly support to NAN, including sponsorship of last April’s conference, without disclosing the amounts.

In 2006, the Rev. Jesse Jackson, a Sharpton rival, accused the retailer of buying silence from critics of its employment practices by trying to “throw money at us.”

At the time, Sharpton rushed to the company’s defense. “Wal-Mart has in no way tried to persuade me with money,” he declared.

NAN, a tax-exempt nonprofit, closely guards its corporate largesse. Most companies also keep the sums secret, and some would not divulge them. The corporations interviewed by The Post viewed their relationships with NAN as friendly and beneficial.

Anheuser-Busch states on its Web site that it gave the group “between $100,000 and $499,000” last year.

Last year, Attorney General Andrew Cuomo found NAN had failed to file years’ worth of financial reports. The group has filed more records, but the AG’s office said it won’t release them pending the US attorney’s probe.

In its 2006 IRS filing, the latest available, NAN reported about $1 million in contributions and $1.1 million in expenses and programs. It owes the IRS $1.9 million in payroll taxes, The Post has learned.

A NAN spokesman said the group is cooperating with authorities “to pay whatever obligations it owes and continues to do so.”

susan.edelman@nypost.com