Big-box chains take their competition to ballot box.

Executives at Wal-Mart Stores Inc. and Costco Wholesale Corp., competitors in the $76 billion U.S. warehouse-club market, have taken their rivalry to a new level: national politics.

Wal-Mart, the world's largest retailer and owner of Sam's Club warehouse stores, gives more money to Republican candidates than any other company. Its top three managers, including Chief Executive H. Lee Scott, donated the individual maximum $2,000 to President Bush, and Jay Allen, vice president for corporate affairs, raised at least $100,000 to reelect the president, earning him the Bush campaign's designation of "Pioneer."

Wal-Mart--two-thirds of whose 3,580 stores are in the "red states" that voted for Bush in 2000--is backing White House policies on everything from trade to limiting overtime pay.

Meanwhile, Costco CEO Jim Sinegal is a Democrat who has said Bush's $1.7 trillion in tax cuts unfairly benefit the wealthy. He opposed the Iraq war and supports Sen. John Kerry for president. He's the only chief executive of a company in the Standard & Poor's 500 Index to donate money to independent political groups formed to oust Bush, records show.

"Wal-Mart is extremely strong in Republican strongholds; they are a red-state retailer," said Amy Bonkoski, an investment adviser at Cleveland-based National City Corp.'s private-client group, which manages about $26 billion, including Wal-Mart and Costco shares. "Costco is stronger in Democratic states. Costco is a friend to labor. Unions hate Wal-Mart."

The differences are based on more than ideology: Each retailer has a stake in the election's outcome in areas from health care to the minimum wage to the way, unions can organize.

Kerry' pledges to induce more employers to insure workers with a $257 billion proposal calling for the government to pay most so-called catastrophic health-care costs--only for companies that provide comprehensive coverage. He would raise the minimum wage and make it easier for workers to join unions.

Issaquah, Wash.-based Costco offers comprehensive health insurance to most of its 78,000 U.S. employees, making it eligible for Keny's plan. That may cut 10 percent, or $35 million, off its annual health care premiums.

Wal-Mart's health plan for its 1.3 million U.S. workers is probably not broad enough to qualify for the savings that Kerry's proposal would bring, since it doesn't cover enough workers.

Fewer than half of Wal-Mart's employees are enrolled in the company health plan, according to figures supplied by the retailer.

The differences are seen in other ways. Costco wouldn't have to raise salaries with Kerry's proposal to increase the minimum wage to $7 an hour, from $5.15 now. It already pays hotdog vendors as much as $16 an hour, and the lowest wage it pays is $10 an hour. That's higher than the $9.96 average wage paid at stores bearing the Wal-Mart name.

Bentonville, Ark.-based Wal-Mart supports the Bush administration's expansion of free-trade agreements and its bid to curtail the number of workers eligible for overtime pay, according to its lobby disclosure reports. Wal-Mart has benefited from the president's opposition to raising the minimum wage, since some employees make less than $7 an hour, and from the Republican-controlled Congress' reluctance to make it easier for workers to unionize. Wal-Mart has no unions; about one-sixth of Costco's workers are represented by labor groups.

"President Bush and his administration have made a real concerted effort to reach out to Wal-Mart and try to understand what our experience is," said Allen.

Wal-Mart and Costco aren't the only companies in the same industry whose executives are on opposing sides in the election. Google Inc. CEO Eric Schmidt is backing Kerry, while Internet rival Yahoo! Inc. CEO Terry Semel endorsed Bush. William Harrison, CEO of J.P. Morgan Chase & Co., is giving more money to Democrats than to Republicans, in contrast to peers at Goldman Sachs Group Inc. Morgan Stanley and Bear Stearns Cos., federal disclosures show.

What makes the Wal-Mart and Costco rivalry stand out is that their political donations are so partisan and both companies are likely to gain if their party wins in November.

IRS disclosure records show that Sinegal and Costco Chairman Jeffrey Brotman each gave $95,000 last December to the fund-raising arm of America Coming Together, a group organizing voters against Bush, and the Media Fund, which is running anti-Bush advertisements.

Wal-Mart's political action committee, the biggest company PAC, gave Republicans 81 percent of its $1.3 million in donations in the past two years, a higher proportion than any of the top 25 corporate PACs, according to PoliticalMoneyLine, a non-partisan, Washington-based group.

Sixty-seven percent of Wal-Man's stores are in the 30 states that voted for Bush and Cheney in 2000, according to a comparison of store-location figures in the Wal-Mart 2003 annual report and election results. Costco's stores are mostly located the coasts, with 208 of its 321 stores in the higher-wage, more union-friendly 20 states that voted for Democrat Al Gore in 2000.

Sinegal makes no apologies for Costco's policies, saying higher wages reduce employee turnover, which lowers training costs. "I'm not a social engineer," he said in an interview. "Paying good wages is simply good business."