there are 2 general rules to avoid penalties for not making timely payments towards your 2025 tax by having sufficient withholding and making timely estimated tax payments
1. they must equal 100% of your 2024 tax. 110% if your 2024 adjusted gross income was $150K or more OR
2. they must equal 90% of your 2025 tax.
we can't see what Turbotax did
the first rule, if met, always works regardless of actual taxes for the next year. however, in your situation with a large capital gain, you would end up owing a significant balance come 4/15/2026.
