What is a Coverture Fraction?

A “coverture fraction” is a fraction that determines how much of an asset is marital. Typically, the coverture fraction is used when dividing defined benefit retirement assets such as government or military retirement.

The numerator for this fraction is the number of years of marriage in which the parties were married in which one spouse was working at a job that accumulated the right to such a defined benefit pension.  The numerator period for the coverture fraction ends when a marital dissolution case (either a divorce or separate maintenance action) is filed.

The denominator for this fraction is the number of years in which one spouse was working at a job that accumulated the right to such a defined benefit pension.  The denominator ends when a spouse stops accumulating credit towards the defined benefit pension—typically due to a job change or retirement.  Often, at the time of the parties’ marital dissolution, the denominator is unknown.  However, through the use of a Qualified Domestic Relations Order (QDRO), the pension plan administrator can determine the denominator when the spouse retires and/or begins receiving the pension.

To illustrate (for ease I will use whole years but the fraction can be calculated by days), if a spouse begins working in a position with a defined benefit plan in 2000, marries in 2005 and retires in 2020, the coverture fraction is 3/4^ths (fifteen years of marriage while the pension accumulated divided by twenty years of accumulated pension).

If a spouse begins working in a position with a defined benefit plan in 2003, marries in 2008, files for marital dissolution in 2023, and retires in 2028, the coverture fraction will be 3/5^ths (fifteen years of marriage while the pension accumulated divided by twenty-five years of accumulated pension).  In this scenario, the actual fraction would not be known until the time of retirement.

For a spouse accumulating a defined benefit pension, it can make sense to file a marital dissolution case before negotiating in order to stop the coverture fraction from increasing.