Income reported on a 1099-B, 1099-DIV, or any other income, is assumed to be earned spread out over the whole year. Payments are only counted as being made when they are made.
Both the IRS and the states want taxes paid more or less evenly over the year, with payments due April 15, June 15, Sept 15 and January 15. If you only make a payment when you file your tax return, then you were underpaid for 12 months on the tax you should have paid in April, you were underpaid for 10 months on the tax you should have paid in June, and so on.
There is a calculation you can do called the annualized income method, when you have a lump sum of income. For example, if you cash out a large position in December, the IRS and state will look at that income and assume it was paid evenly over the year, and they will look for the 4 estimated payments. You will be under-paid even if you made a lump sum payment by January 15. You can use the annualized income method to show that your income was uneven but your tax payments in each quarter were appropriate for the income in each quarter.
That won't work for you for 2 reasons. First, if you are not making a payment for the 4th quarter on January 15, then you are late on all your payments even if you pay in full in March or April. And second, if you are receiving dividends throughout they year, that income is received by you over the course of the year and you should be making payments each quarter -- the annualized income method won't help because you don't have a single lump sum of income to account for. Your income is spread out over the year, you just aren't paying the taxes over the year.
Turbotax includes the penalty calculation forms but it does not always automatically ask you to complete them because it does not recognize every situation where you might owe a penalty. You can run the interview manually, look for it in the state module. (The federal penalty form is under "special circumstances" in the federal section.
Another way to avoid the penalty is to make quarterly estimated payments for the due dates I gave. You can make electronic payments at the state tax web site. If you over-pay the estimate, you get the difference back as a refund. You need to make estimated payments that equal 90% of your eventual tax bill, or 100% of last year's tax bill.
For example, suppose that in 2023, your total tax was $10,000. You expect that withholding from your job will be $8000 in 2024. If you made 4 quarterly estimated payments of $500 (so that your total payments for 2024 were at least $10,000) that should avoid a penalty, even if your dividends and gains in 2024 are more than 2023. (If your gains and dividends are less, your tax is less and you get a refund.)
At this point in 2024, your best hope is to make an estimated payment before January 15, 2025, so that your total withholding plus payments is 100% or more of your 2023 tax bill. If you wait until April 15 to pay, you will get hit with another under-payment penalty even if you have paid in full when you file.
