What Is a Cross-Tested Profit-Sharing Formula in a 401(k) Plan?
A profit-sharing formula sounds like it should divide money the same simple way for everyone, but one common design does something more mathematically interesting behind the scenes.
The short answer
A cross-tested profit-sharing formula allocates employer contributions to different groups of employees at different rates, then tests whether the plan is fair not by looking at the contribution amounts themselves, but by projecting what each contribution would grow into by retirement age. Because older employees have less time for a given contribution to compound, this method can allow a plan to direct proportionally larger contributions to older or more senior employees while still satisfying the government’s nondiscrimination testing requirements.
Why testing looks at projected benefits, not just dollars
In a standard profit-sharing plan, contributions are often calculated as a flat percentage of each employee’s pay, and testing simply compares those percentages across income groups. Cross-testing takes a different approach: it converts each employee’s actual contribution into an estimated future retirement benefit, using assumptions about investment growth and the number of years until a set retirement age. Two employees receiving very different contribution amounts today can, under this method, be shown to be receiving comparable projected benefits once age and time horizon are factored in.
Why age changes the math
The mechanics hinge on a straightforward idea: a dollar contributed for an employee close to retirement has far fewer years to grow before it’s needed than a dollar contributed for a much younger employee. Under cross-testing, that shorter runway means an older employee needs a proportionally larger current contribution to reach the same projected retirement benefit as a younger employee receiving a smaller contribution. This is what allows a cross-tested formula, when combined with structures like an age-weighted allocation, to direct noticeably larger contribution percentages toward older, often more senior employees without failing the required nondiscrimination tests.
Why small, owner-heavy businesses use it
This formula shows up often in smaller companies where the owners or top earners are also among the oldest employees. Because cross-testing can concentrate larger contributions on older participants while still passing the government’s testing requirements, it lets a business direct a meaningful share of the profit-sharing pool toward its principals, provided the plan still delivers a testing-adequate benefit to the rest of the workforce. This is closely related to what’s sometimes called a new comparability plan, which groups employees into separate classes for exactly this kind of differentiated allocation.
What employees should understand about it
For an employee, the practical effect of a cross-tested formula shows up as a profit-sharing percentage that may look different from a coworker’s, even at similar pay levels, simply because of an age difference. It’s not a sign of favoritism outside the rules — it’s the intended result of a testing method built around projected benefits rather than flat percentages. The plan’s summary plan description should spell out which formula is in use and how contributions are calculated for each defined group.
The bottom line
Cross-testing is a technical mechanism, but its real-world effect is simple to describe: it lets a 401(k) profit-sharing contribution reflect how much time each dollar has left to grow, not just how much pay it’s based on. Anyone trying to understand why their own allocation looks the way it does may find it useful to ask their plan administrator which formula the plan uses, since the answer shapes the contribution far more than the headline profit-sharing percentage might suggest.