The Internal Revenue Service’s annual “dirty dozen” list of the top 12 tax scams in the United States includes schemes that involve charities—in particular, the misuse of noncash donations.

The IRS says that it’s investigating cases in which donors try to maintain control over donations or income from contributions of assets.

The tax agency says it has seen cases in which several charities claim the value of the same donated products.

“Often these donations are highly overvalued or the organization receiving the donation promises that the donor can repurchase the items later at a price set by the donor,” the IRS says.

The Pension Protection Act of 2006 imposed higher penalties for inaccurate appraisals of noncash gifts, says the tax agency.

Last month, the IRS imposed a fine on Food for the Hungry, an international charity, for allegedly misleading the public about the value of its noncash donations. Food for the Hungry disputes the IRS’s action.