This is the first time in 35 years that I am making estimated tax payments instead of simply relying on withholding. Based on my (perhaps faulty) assessment of the situation, it appears that I cannot avoid underpayment penalties when I file next year. Am I overlooking or misunderstanding something?
During the first payment period, my taxable income, ergo my est tax, was very low. In the second period, I had a windfall due to exercising employee stock options (wage income subject to withholding) and liquidating a large amount of stock (capital gain; no withholding). The second-period taxable income is 10 times the first period's. But the withheld taxes are sufficient to cover my total expected year-end tax liability, let alone the minimum payment for the period. The problem seems to be with the very low first-period payment. When I look at Form 2210, I do not meet the safe-harbor conditions in Part I. I do not qualify for the Short Method in Part II. If I use the Regular Method (Part IV), the first required installment is about 25% of the total tax liability -- far more than I actually paid due to the very low first-period taxable income. If I use the Annualized Income Method (Sched AI), my actual second-period payment is substantially less than the computed required payment because the method would have me multiply the one-time by 2.4, as if I expect the windfall to continue for the remainder of the year. (Not!) So both methods seem to result in a substantial underpayment penalty. And yet I believe I paid prepaid the taxes in a timely manner, having paid the full amount of taxes (and more!) due to the windfall as well as covering my normal expected taxable income. Am I misunderstanding Form 2210?
Do I have any other recourse to avoid the "underpayment" penalty? According to Form 2210 instructions, there is a procedure for requesting a waiver of penalty. But based on my (perhaps faulty) interpretation, I do now qualify. Although I retired in 2005, I am not yet age 62; nor am I disabled. The penalty could be waived due to "unusual circumstances". But the examples are casualty and disaster. I do not know if "windfall" would qualify ;-). Do I misunderstand the waiver and its (in)applicability to me? If any tax professionals in this forum have experience with similar situations (I would think it is not so uncommon), I would appreciate any guidance in understanding how I might (legally) avoid the underpayment penalty, given that I believe I have indeed followed the "pay as you go" principle. (That is, I am not attempting any kind of tax-avoidance scheme whatsoever.)