I understand basically how Safe Harbor rule applies to high income cases, which is that if you pay at least 110% of your previous years taxes, then there are no penalties when you pay the full remaining amount due at filing time before April 15th. But, if you were to take an extreme case, where let us say your Previous Year Tax was $50K, and you paid estimated taxes of $55K (four equal quarters), but due to a one-time event your Current Year Tax due was much much higher (say 5x higher! which can happen due to many reasons such as property sale, lottery, estate windfalls, IRA conversions etc.), so you had $250K+ due. Does that mean that if one pays the remaining amount of ~$200K, there is no penalty as one has met safe harbor? If one knows that is the case, can people not invest that delta of $200K in a CD or something and earn a reasonable amount of interest by meeting the safe harbor? I am trying to figure out if there is actually a catch and safe harbor does not suffice for Federal. Thanks!
