Before Leonard Smith lost his battle with cancer in 2008, he worked with his financial advisors and attorneys to make sure his children received the balance of his retirement funds when he died.
A single mistake, however, thwarted his well-laid plans. Family members realized a year after he died that his IRA beneficiary form was filled out incorrectly. Instead of specifically listing the names of his children along with the percentages designated to each heir, Smith wrote: “To be distributed pursuant to my last will and testament,” where the disbursement of funds was spelled out.
But Smith’s failure to complete the form correctly invalidated the document, making his surviving spouse the beneficiary by default.
“I had no idea that a will could be trumped by an IRA beneficiary form,” Deborah Smith-Marez, 50, Leonard’s daughter, told Yahoo Finance.

Man’s mistake cost his children $400,000 of an IRA inheritance – Yahoo Finance