This notice of proposed rulemaking by cross-reference to temporary regulations relates to the portability of the deceased spousal unused exclusion (DSUE) amount as enacted by section 303 of the Tax Relief, Unemployment Insurance Reauthorization, and Job Creation Act of 2010, Public Law 111-312 (124 Stat. 3296, 3302 (1997)). The proposed regulations provide guidance to married individuals on the ability to transfer or "port" the DSUE amount of the first spouse to die to and for the benefit of the surviving spouse in determining the surviving spouse's unified credit amount. The proposed regulations also provide guidance to a surviving spouse on the application of the DSUE amount to lifetime transfers and transfers taking effect at death.