Prop. Regs. 20.2010-1(c); Reg-106706-1
If a client gifts $11.4M in 2019 and dies in 2026 when the exemption is back to $5M. The $11.4M is an adjusted taxable gift in the estate tax calculation so do you owe estate tax on the additional $5M. IRS held that taxpayers will not have this problem.