An employer contribution shown on a pension statement is not always the employee's to keep. Vesting rules determine when ownership transfers, and leaving before that point can forfeit the amount.
Two pots with different owners
Contributions made by the employee are theirs immediately in most systems. The money was their income and simply arrived in a different account.
Employer contributions are made under the terms of the scheme, and those terms may require a period of service before the amount becomes unconditional.
Until that condition is met the balance appears in the account but remains conditional, which statements do not always make obvious.
Cliff and graded schedules behave differently
A cliff schedule transfers ownership of the whole employer balance at a single point. Before it, nothing is retained; after it, everything is.
A graded schedule transfers ownership in increments across several years, so a departure part-way retains a proportion rather than nothing.
The shape matters most when a departure is being considered near a threshold, because the amounts involved can be significant relative to a salary change.
The purpose is retention
Vesting exists to make leaving costly at the point where an employer's investment in a new employee has not yet been recovered.
It functions as deferred compensation, which means the headline value of a package overstates what is actually received by someone who does not stay.
Comparing offers therefore requires knowing both the contribution rate and the schedule attached to it.
Matching rates and caps set the real value
Employers commonly match contributions up to a limit, sometimes at less than one for one. Contributing above the cap attracts no additional match.
Contributing below the cap forgoes part of the available employer contribution, which is why the match threshold is a natural reference point for a contribution decision.
Some schemes require an application or an active election, so the match is not always received by default.
What happens on leaving
Vested balances generally remain the employee's, whether left in the scheme or transferred, subject to the scheme's rules and any minimum service conditions.
Unvested employer amounts are typically returned to the employer or to the scheme, and they do not follow the member.
Rules on vesting, transfers and treatment on leaving vary widely by country and scheme, so the scheme documentation is the only authoritative source for any individual case.