About 20 states have adopted laws that would effectively keep companies from using the decades-old tax loopholes in Delaware. At stake are tens of billions of dollars in annual tax receipts, funds that states say they need during this recession.

Critics of the arrangement in Delaware say it cheats state governments out of money. Delaware, these people say, has created its own onshore Cayman Islands. Even the Swiss are complaining, claiming that the United States is letting this homegrown haven flourish even as the I.R.S. pursues offshore shelters.

Defenders of the arrangement  corporate executives, tax lawyers and, unsurprisingly, Delaware officials  rebuff such criticism. Mailbox subsidiaries like the ones along North Orange Street do nothing to minimize companies’ federal tax bills, they say. Corporations must still pay Uncle Sam. Moreover, these people say, many companies are drawn to Delaware for its business-friendly laws and courts, not to save on taxes.

That is certainly the view at 1209 North Orange Street, a nondescript low-slung building at the corner of West 13th Street. This address serves as a tax minimizer for dozens of brand-name companies, among them Dillard’s, the department store chain based in Little Rock, Ark., and Kentucky Fried Chicken, which is part of Yum Brands of Louisville, Ky. All of them, and nearly two-thirds of the Fortune 500, have tax-exempt subsidiaries at this address to reduce their state tax bills.

Jerry Daniel, the vice president for government relations at the Corporation Trust Company, which runs 1209 North Orange, does not see what all the fuss is about. After all, the arrangements are legal.