Estimated tax payments

@dande36 

That really depends on your entire income for the year,

The withholding you have set up to be done may be more than needed, or less than needed.

For example:  If you have 10% of the distribution withheld, but the distribution pushes you into one of the 20%+ tax brackets, then the amount you have withheld may not cover all the tax you need to pay for the year.....based on ALL your income from all sources.   But that also depends on any/all other withholding you have done for the year....it's all added together.

Essentially, you should try to have your withholding set to cover exactly the taxes that will be assessed when you file next year. True: that can be tough to figure out ahead of time...especially if you have investments in Mutual funds that don't pay out until the end of the year and can vary widely.  You just do the best you can to balance things out.