An investment policy statement fixes the standard for judging a portfolio before performance is known, which is the only point at which it can be agreed fairly. Without one, the goalposts move with hindsight and accountability rests on memory.

Ask a family, trustee board or charity what their portfolio is trying to achieve and the answer is often clear. Ask where that objective is written down and the answer is frequently less certain. That is the gap an investment policy statement fills.

What it actually is

An investment policy statement (IPS) is a written document setting out how a portfolio should be managed and judged. At minimum, it records the return objective, acceptable risk, time horizon and liquidity needs. It should also set out the strategic asset allocation, who holds authority for different decisions and how the portfolio will be reviewed.

Why writing it down matters

Without a document, standards for judging a manager tend to move. A result that looked acceptable when it was made gets reassessed with hindsight once markets turn, and the goalposts shift without anyone deciding to move them. A written IPS fixes the standard in advance. It prevents success and failure being redefined after the event. It also protects continuity. Trustees change. Family members take on and hand off responsibility. A committee's collective memory of why an allocation was chosen does not survive personnel turnover, but a document does.

How it connects to the rest of the framework

The IPS is the document. Strategic asset allocation is the destination it sets. Rebalancing and portfolio management are the mechanisms that keep the portfolio within the boundaries the IPS defines. Each depends on the one before it. A portfolio can drift from its allocation. An allocation can drift from what the IPS specifies. Without the written document, there is nothing to measure the drift against.

Keeping it current

An IPS is not meant to be rewritten every time markets move. It should be reviewed on a fixed cycle, typically annually, or when circumstances change materially: a liquidity event, a shift in a charity's spending needs, a change in trustees. Reviewing it more often than that risks the opposite problem: chasing recent performance rather than sticking to an agreed plan.

The document itself is unremarkable. What it prevents is more important: ad hoc decisions, standards that move with hindsight and accountability that depends on memory rather than evidence.