Perhaps that is what mmgoebe raised but I suspect that he misinterpreted the OP's OP. It would be rare that someone would take a $770k lump sum from a defined benefit pension plan as a taxable distribution, pay the tax all at once and then buy an annuity with the after-tax proceeds because the progressivity of the tax rates would slaughter you.
I responded so the OP would not get confused by the tangent that you two created and think that he had to pay taxes if he took the lump sum.
If something cannot endure laughter.... it cannot endure.
Patience is the art of concealing your impatience.