@dmertz I have a question about using 2017 year-end balance to calculate the tax. Why not using the Traditional IRA and 401(k) balance on the day the brokerage firm takes the distribution amount from the balance? A brokerage customer in 2017 had the RMD the first time so he asked his brokerage firm to do RMD distribution in early 2017 (15Feb2017). The brokerage said they applied an IRS formula to calculate the distribution based on the balance on 15Feb2017, which would be very different than the year-end balance. I have difficulties reading and understanding the IRS web link you provided. Thank you.
