A higher income taxpayer bumps up from $300k in AGI to over $1 million, but has already had over 110% of their prior year tax liability withheld from their paycheck. Given the safe harbor, I don't see any need for them to make any additional tax payments prior to filing their tax return if they'd rather hold onto the money. While salary and related withholdings increased due to salary increases from $300k to about $500k, they also have additional capital gains of about $400k with no taxes withheld at this point. Based on satisfying the 110% of prior year total taxes owed, I can't see any impact to their tax liability by holding out until filing their 2021 tax returns, but want to be sure that's correct.