How will TurboTax handle 2021 taxes if Biden tax increases end up being retroactive to April 2021?

[Nearing70]

I use Turbo Tax near the end of the year to estimate my likely tax liability so that I can decide whether to take any voluntary IRA distributions (I'm retired, older than 59-1/2, and younger than 70-1/2).  

For example, if my normal income and capital gains are so low that I will have no tax liability, I might decide to take some money out of my IRA up to the point where I just begin to owe tax.  I would normally use the What-If feature in TT 2020 with the 2021 tax rate flag checked to do this.

But 2021 may be a bit complicated.

Assuming Biden gets his tax increases through by the end of 2021, I have read that some of them are likely to be retroactive to April 2021 (to avoid nasty runs on the stock market etc.).  On the other hand, Biden may not get any of his tax increases through this year.  But time is getting short and we may not know one way or the other until just before the end of year, when it might be too late to organize an IRA withdrawal.

Is TurboTax building in any contingency calculations into TT 2020's capability to estimate 2021 taxes?

If not, can we assume Turbo Tax 2021 will at least contain the user interface and calculation to handle the split between what is subject to retroactive taxes and not?

Thanks!

[DoninGA]

The proposed increases to the tax rates are all showing to start in tax year 2022.  So would have no effect on tax year 2021.

[Nearing70]

Thanks DoninGA.  When you say "are all showing to start in tax year 2022", do you mean that's how TurboTax 2020 is currently calculating 2021 taxes (using What-If), or are you saying you don't believe any of the tax increases will end up being applied retroactively?

I have read articles that suggest a retroactive application is certainly possible, especially regarding any increases in capital gains taxes.  The logic being that, without any retroactive application, there would likely be a big sell off in the markets at the end of 2021 as investors suddenly rush to realize their capital gains before Jan 1, 2022.  

[DoninGA]

The What-If 2021 tax rates are the rates for tax year 2021as defined by the current Tax Code.

There are many proposals being floated by the Congress, one being to increase the long term capital gains tax rate to 25% from the current 20% for asset sales after September 13, 2021.  As with all proposals in Congress, changes to the tax code has to be approved by both houses and then signed into law by the President.  Whether any of the proposed tax code changes ever become law is anyone's guess.

For TurboTax, any calculations are wholly dependent on the IRS interpretation of the tax code changes and will not be incorporated into the TurboTax software until written and approved by the IRS.