Turning a stock into a flow

A pile does not buy groceries.

Every plan that ends with a number has one more step in it that almost nobody thinks about until they arrive: converting a stock into a flow. Turning an amount into a monthly payment, reliably, for a length of time you do not know in advance.

The conversion has rules, and several of them are counterintuitive enough to ruin plans that were otherwise sound.

The distinction that is smaller than it feels

There is a strong intuition that income from an asset is fundamentally different from selling part of the asset — that one is sustainable and the other is eating the capital.

Arithmetically, that intuition is mostly wrong.

Suppose an asset worth 100 produces 4 of income and does not grow. After the income is paid, you hold 100 and have 4. Suppose an otherwise identical asset produces nothing and grows to 104. Sell 4 and you hold 100 and have 4.

Same position, same total, different route. The thing that matters is total return — what the asset produced plus what it appreciated — and how much of it you removed. Which door the money came through is largely a matter of form.

Predict

Given that, why do so many plans insist on living only on income and never selling anything?

Choose one answer

Because it is arithmetically saferBecause it removes a decision, and a rule that removes decisions is worth something even when the arithmetic is indifferentBecause income is taxed more favourablyBecause assets that pay income are better assets

Lock in answer

Four rules of the conversion

Liquidity decides which pieces you can sell, and when. A pile made of things that take four months to sell is a pile you cannot draw on in a bad month. Track 5 called illiquidity a cost that arrives exactly when you cannot pay it; this is the phase of life where it arrives.

The order of returns matters far more than the average. Withdrawing from a falling portfolio sells more units to raise the same amount, and those units are never there for the recovery. Two people with identical average returns and different orderings can end in completely different places, which is a whole lesson in the arithmetic track and the single largest risk in this one.

Reaching for yield is reaching for risk. An asset paying a much higher income than comparable assets is being paid for something — worse credit, less liquidity, a shorter life, or a payment that is partly a return of your own money. There is no arrangement where a higher payment arrives for free.

Conversion has friction. Selling costs something. Contracts have loadings. Currency conversion has spreads. None of these are large in one transaction and all of them compound across thirty years of monthly transactions.

Not the same thing

Yield

The income an asset pays out, as a share of its price, without the asset being sold.

Measured in

Percentage paid per year

For example

An asset priced at 100 that distributes 4 a year.

Chase it alone and

Selecting for it narrows what you can hold and quietly selects for the things being paid to take a risk somebody else declined.

Total return

Everything the asset earned — the income it paid plus the change in what it is worth.

Measured in

Percentage per year, income and price change combined

For example

An asset that paid 1 and rose by 3 returned the same as one that paid 4 and stood still.

Chase it alone and

It requires deciding what to sell and when, which is a judgement made repeatedly under exactly the conditions where judgement is worst.

Which is which? Put each one on a side.

• A holding paying out more than it earns each year

  YieldTotal return

• A household that wants a predictable amount arriving monthly with no decisions

  YieldTotal return

• Comparing two assets to decide which was the better thing to have owned

  YieldTotal return

The one risk the pile cannot diversify away

You do not know how long the money has to last.

Every other risk in the conversion can be reduced by holding more things, or holding safer things, or spending less. This one cannot, because the horizon is a property of a single life and there is no pooling available to an individual.

Which is what the third conversion mechanism exists for. Exchanging a pile for a contracted income transfers exactly that risk to an institution, which can pool it across thousands of people the way an insurer pools anything else. Track 4 explained how that pooling is priced; the same logic applies here, including the part where the price is above the expected cost.

The trade is the familiar one: a worse expected outcome in exchange for the removal of a tail. Here the tail is living a very long time with nothing left.

Check

Someone converting a pile into income is deciding between a mixture and a single mechanism. What consideration argues most strongly for a mixture?

Choose one answer

The three mechanisms fail in different conditions, so covering the fixed costs with the most predictable one leaves the rest free to be flexibleMixtures generally produce higher returnsIt is easier to explain to familyIt reduces the amount of money required

Check answer

Worth remembering

• A pile becomes a payment in exactly three ways: what the assets produce, selling pieces, or exchanging the pile for a contracted income.
• Income and selling are closer than they feel — what matters is total return and how much of it was removed.
• Never selling is a behavioural rule rather than an arithmetic one, and it costs the range of things you can hold.
• The order returns arrive in matters more than the average once withdrawals have started.
• Not knowing how long the money must last is the one risk an individual cannot diversify, which is what a pooled income contract is for.