Estimated federal tax payments, withholding and penalties

[knussml1]

Will I be assessed an underpayment penalty if I have a substantial capital gain in the 2nd quarter, make no estimated payment, then increase my withholding so the total annual withholding exceeds 110% of prior year's tax minus credits?

[DMarkM1]

No.  You will avoid the underpayment penalty if your withholding/estimated tax payments exceed 110% of your prior year tax minus credits.