For post-divorce asset transfers between ex-spouses who are be both U.S. citizens:

a. transfer occurring within 10 years of the date of divorce will automatically be tax free

b. transfer occurring within one year of the date of divorce will automatically be tax free

c. Only transfers of assets that are not 'incident to divorce"will be tax free

d. transfer occurring within 6 years of the divorce but not required under a divorce property settlement agreement will automatically be tax free