The entry in box 5 may include any of the
following:
(a) designated Roth contributions or
contributions actually made on behalf of the employee
over the years under the plan that were required to be
included in the income of the employee when contributed
(after-tax contributions),
(b) contributions made by the
employer but considered to have been contributed by the
employee under section 72(f),
(c) the accumulated cost of
premiums paid for life insurance protection taxable to the
employee in previous years and in the current year under
Regulations section 1.72-16 (cost of current life insurance
protection) (only if the life insurance contract itself is
distributed),
(d) premiums paid on commercial
annuities. Do not include any DVECs, elective deferrals,
or any contribution to a retirement plan that was not an
after-tax contribution.
For more detail on 1099R, see here: https://www.irs.gov/pub/irs-prior/i1099r--2019.pdf
