Nondividend Distributions

It is not paid out through earnings (profits) or a mutual fund. It is a kind of return of capital to the owner.

It is a kind of adjustment that reduces the basis of the investing solutions. Due to reductions, one may not have to pay tax until the stock has fully recovered. 
If a person buys share ABC in 2017 for $10 and gets a dividend of $10 on each unit.

Assuming the firm calculates the percentage that 55% of the dividend is non-dividend, then the shareholder can report the change in qualified units for final submission for the tax year as the reduction in the basis is not taxable but one may have to pay at the time of sale.

If investors buy stocks in a firm in different time slots, one may not identify the ones that are non-dividend.

So they need to reduce the basis of previous purchases to zero, then in case of such distribution one can get capital gains that can be either short term or long term.

For example- if you hold $1000 in 50 units and you get a distribution of $200. The original basis is $20 a share but with the new adjustment, it will reduce $200/50 i.e. $4 from each to get you $ 16. Since the value is less, there is no tax due.

The taxpayer does not need to report for such distribution, in case the capital gain is less.