Rules on Portability of Unused Exemption of Deceased Spouse

In addition to increasing the federal estate tax exemption to $5 million, the 2010 estate tax law changes also permit the surviving spouse to utilize the unused portion of the deceased spouse's federal exemption. To enable this process, the estate of the deceased spouse must file a federal estate tax return even if the return would normally be unnecessary due to the estate being less than $5 million.