The word pension covers two structurally different arrangements, and the difference determines who bears the risk if things go badly. Almost everything else follows from that.
Defined benefit
The employer promises a specified income in retirement, calculated by a formula — typically years of service multiplied by a fraction of salary.
The employer is obliged to deliver that income regardless of how the investments perform.
Which places investment risk, longevity risk and inflation risk on the employer, and gives the member certainty.
These have been closing to new members across the private sector for decades, for reasons that follow directly from that risk allocation.
Why they closed
Three things happened together.
People lived longer than the assumptions used when the schemes were designed, which extended the payment period.
Interest rates fell for an extended period, which raised the present value of future obligations enormously, since a promise of future payments is discounted at prevailing rates.
And accounting rules changed to bring scheme deficits onto corporate balance sheets, making the volatility visible to shareholders.
Any one of these would have been manageable. Together they made the promise far more expensive than it had appeared.
Defined contribution
The employer contributes a defined amount. What emerges depends on contributions, investment returns and charges.
There is no promise of an outcome.
Which places all the risk on the member, and gives the employer a predictable cost.
That shift is the single largest change in retirement provision over the past forty years, and it happened gradually enough that its significance was underappreciated at the time.
The three levers
In a defined contribution arrangement, the outcome depends on how much goes in, how long it compounds, and what it costs.
Contribution rate is the largest lever and receives the least attention, because it requires giving up current income.
Time is the second, and it cannot be recovered later, which is why early contributions matter disproportionately.
Charges compound against you the way returns compound for you. A difference of a fraction of a percent annually becomes substantial over decades.
Employer matching
Where an employer matches contributions up to a limit, contributing below that limit forgoes money that was available.
This is one of the few points in personal finance where the arithmetic is unambiguous, and take-up below the match threshold remains common.
The usual explanations are inertia and cash flow, and the first is more common than the second.
Automatic enrolment
Several countries have introduced systems that enrol employees by default with an opt-out.
Participation rose dramatically, which is the clearest demonstration available that default settings drive behaviour more than incentives do.
The subsequent question has been contribution adequacy, since default rates were set low to limit opt-outs and low rates produce low outcomes.
Escalation mechanisms that raise the default over time have been introduced in some systems to address this.
The decumulation problem
Accumulating is the part everyone discusses. Converting a pot into income for an unknown number of years is genuinely harder and gets far less attention.
An annuity converts the pot into guaranteed income, transferring longevity risk to an insurer, at a price that depends heavily on interest rates at the moment of purchase.
Drawdown keeps the pot invested and withdraws from it, retaining flexibility and the risk of exhausting it.
The sequence of returns matters enormously here — poor returns early in withdrawal do far more damage than the same returns later, because withdrawals crystallise the losses.
This is a well documented effect and it is not intuitive.
The state layer
Underneath both sits whatever the state provides, which varies enormously between countries in generosity and structure.
It is generally the foundation on which private provision sits rather than a supplement to it, and understanding what it will actually provide is the starting point for any planning.
Most systems provide a forecast of entitlement based on recorded contributions. Obtaining it is straightforward and few people do.
The necessary caveat
Retirement decisions involve tax, means-tested benefits, personal circumstances and timescales that make general commentary close to useless for any specific person.
What is written here is a description of how the arrangements are structured. Anyone making decisions should be speaking to a regulated adviser, and the cost of that advice is generally small relative to what is at stake.
Charges and where they hide
Worth being specific, since the effect compounds over decades.
An annual management charge is the visible figure, and it is frequently not the whole cost.
Transaction costs within the fund, platform or administration fees, and charges on underlying funds in a multi-layer structure can all sit alongside it.
Disclosure requirements in most markets now mandate a total cost figure, which is the number worth finding.
Default funds
Most members of a defined contribution scheme never make an investment choice and remain in the default.
Which makes the design of that default the single most consequential decision in the whole system, and it is made by scheme trustees rather than by members.
Defaults typically follow a glide path, holding more growth assets when the member is younger and shifting toward less volatile assets as retirement approaches.
The assumptions behind that glide path were frequently set when annuity purchase at a fixed retirement date was the norm, and many have been redesigned since drawdown became common, because the appropriate shape differs.