Sporting a tax return that includes a charitable donation of an Oldenburg rather than an old sofa? Or flush with an income in the seven-, eight-, or nine-figure range?

As affluent taxpayers map out their tax strategies, experts say they should pay close attention to following certain red-flag transactionss as they can act as audit magnets for the Internal Revenue Service.

Earned It? Then Report It.

"You always want to be careful and report all of your income," says Alan Olsen, a certified public accountant and managing partner with Greenstein, Rogoff, Olsen & Co., which specializes in providing financial advice to high-net-worth clients.

Sure an audit can result in painfully large penalties over rejected deductions. But fail to report income from the sale of a business, stocks sold, or a hedge fund that blossomed, and the check you may write in that case could be to a lawyer trying to keep you out of jail.

Weekend Vitner? Probably Not a Business.

Many founders believe that once they sell that start-up they nursed through 19-hour days, it's time to indulge other interests. But make sure, says Olsen, that you don't write off expenses from a lavender farm in Provence or vineyard in Napa as business deductions if they're really just hobbies and not producing an income.

"If you buy a winery, make sure you're out there cutting vines, and stay actively involved," Olsen says. "Don't go up there just once a year for a weekend, and expect the I.R.S. to allow your business loss."

Renting Out a Country Home?
Don't Camp Out for Summer.

Again, if you're looking for a vacation home, great. But if you're spending a month in your Tahoe condo for some late season skiing, and renting the space the rest of the year, it's no longer a rental property according to the I.R.S.

"Real estate is always a good investment to shelter some of your income," says Olsen. "But if you're buying something as an investment property, you can only stay less than 14 days a year. Otherwise, it's a second residence."