Megan McArdle:

I find it hard to believe that none of the liberal commentators breathlessly celebrating Wal-Mart’s “capitulation” on national health care have even entertained the most parsimonious explanation: that Wal-Mart is in favor of this because it raises the barriers to entry in the retail market, and hammers Wal-Mart’s competition. Yet somehow, this appears nowhere in any of the analysis.
Wal-Mart is always going to have a seat at the table when employer mandates are discussed, because Wal-Mart is the nation’s largest private employer. Target and Macy’s probably won’t have a seat at the table. So Wal-Mart can influence the rules in ways that benefit Wal-Mart at the expense of the competition. This is partly because the regulators often cycle into jobs at the firms they regulate, but also simply because the regulator’s attention is finite, so being consistently at the table allows you to shape their views over time.

Doc Bainbridge has much more. An excerpt:

In fact, however, Wal-Mart has been suckling at the government teat for decades, transferring costs to the tax payer whenever possible.
Indeed, Wal-Mart is heavily dependent on government subsidies. Wal-Mart routinely gets sales and property tax abatements when it opens a new store, to cite but one example. According to a 2004 study (albeit one funded by a union) the subsidies can amount to as much as 12 million dollars per store. Additional de facto subsidies come when uninsured or under-insured Wal-Mart employees get health care at government expense. Supporting government-run health care looks like a sop to the politicians who control the subsidy tap.
I examined Wal-Mart’s dependence on government subsidies back in 2006 for TCS Daily, writing that:
… both the left and right implicitly cast Wal-Mart in the role of free market capitalist. What’s missing from the debate is the extent to which the Wal-Mart story really is the antithesis of laissez-faire capitalism. When you look under the rug, it turns out that Wal-Mart is a beneficiary of corporate welfare.
When Wal-Mart plans a new store, it typically asks local and county governments for an array of benefits, principally in the form of various economic development subsidies:
Infrastructure assistance in the form of new or expanded roads and utilities servicing the store location.
Sales tax abatements.
Property tax abatements.
Income tax credits.
Enterprise zone treatment for the store location.
Eligibility for job training programs.
Eligibility for tax exempt industrial revenue bond financing.
Economic development loans and grants.