Hounded by charges that the U.S. government overstates the amount of federal contracts that go to small ventures, the Small Business Administration unveiled a plan Tuesday to eliminate loopholes that have allowed large corporations to be counted as small contractors.

The centerpiece of the effort: regulations requiring companies to recertify they are small after every merger or company acquisition, or five years into a long-term contract.

The changes are particularly relevant in Florida, where 98 percent of all companies are small and examples of large corporations squeezing through those loopholes abound. For example, from 2001 to 2004, Tampa's Safety Equipment Co. received millions of dollars' worth of small-business contracts even though it had been bought by Fisher Scientific -- a Fortune 500 company with more than 17,500 employees and annual revenue of almost $5 billion.

Under previous rules, this was perfectly legal. Companies could keep their small-business status for the life of a deal -- often up to 20 years -- even if they were later swallowed up by a larger corporation or outgrew the size limits for their industry.

Under the new regulations, effective June 30, Safety Equipment would have been required to declare its new size when it was bought by Fisher in 2001.

The new rules will not strip small-business contracts from companies that have grown too large, but would bar the government from counting such deals toward its annual goal of channeling 23 percent of all federal dollars to small ventures.

"This regulation will go a long way toward ensuring that contract awards get in the hands of small-business owners, federal agencies get the proper credit toward their small-business contracting goals, and small-business contract awards are fairly and accurately reported," SBA Administrator Steven Preston said in a statement. "It is a win-win situation for everyone."

But some small-business advocates said the rules don't go far enough.

By establishing a five-year window before existing contractors have to recertify their size, the government is giving a pass to large companies already performing small-business contracts, said American Small Business League President Lloyd Chapman.

Chapman's group has been pushing annual size recertification, a recommendation first proposed by the SBA's inspector general's office a few years ago.

"This is smoke and mirrors," said Chapman of the new regulations. "It allows large corporations to keep small-business contracts for five more years."

Along with closing those loopholes, the SBA said it will also institute a Small Business Procurement Scorecard to "more aggressively track and monitor" contracting at 24 federal agencies, and hire additional personnel to identify small-business contracting opportunities.

A Miami Herald review of federal contracts performed in Florida during fiscal year 2004 found that more than half of the state's top 20 small-business contractors were actually large corporations with more than 500 employees. Some had started off small and grown large on the back of lucrative contracts, while others had been absorbed by larger companies.

Nationally, the rules were problematic, too, creating embarrassing anomalies where corporate titans such as Bechtel and IBM would appear on the government's list of small-business contractors.