I understand that required distributions are calculated based on dividing the the balance by life expectancy. My assumption has been that the balance figure used is the ending balance for the prior year. For example, to calculate the distributions required in 2018, the ending balance for 2017 is used.

Is it necessary to adjust distributions during the year if the balance increases significantly? Using the example above, if the balance increases 20% during 2018, even after distributions, is additional distribution required before the end of 2018 to meed minimum distribution requirements?

Thanks in advance for any clarification.

I understand that required distributions are calculated based on dividing the the balance by life expectancy. My assumption has been that the balance figure used is the ending balance for the prior year. For example, to calculate the distributions required in 2018, the ending balance for 2017 is used.==>I guess so ; Generally, your RMD is determined by dividing the adjusted market value of your tax-deferred retirement account as of Dec 31 of the prior year by an applicable life expectancy factor. I guess you need to contact retirement admin for professional help.

Is it necessary to adjust distributions during the year if the balance increases significantly? Using the example above, if the balance increases 20% during 2018, even after distributions, is additional distribution required before the end of 2018 to meed minimum distribution requirements=====>as mentioned above. Please contact retirement plan professional for more accurate help in detail.

This is not a complicated question and the answer does not depend on any particulars to my situation. It's a simple matter of what the IRS requires and should be common knowledge to anyone who is an IRA beneficiary.

I suspect that the answer is no, you don't need to adjust your withdrawal during the year and that you simply use the increased year-end total for the following year's calculation. But there's no clear information on the subject available (which is in part why I suspect the answer is no, lol).