The volume ends at the point where a holding must become a payment. A worker has a bank balance, an investor a bond, a proprietor a building, and each may be wealthy enough to meet an obligation in principle. But the obligation falls due today. The bank balance can ordinarily be transferred in the settlement system that accepts it; the bond must be sold or pledged; the building may require weeks and a willing buyer. What separates them is not simply how much they are worth. It is the ease, cost, and reliability with which they become the thing the creditor will accept. The earlier Liquidity called this the likeness of money. The final plate asks how that likeness is made, and why it can disappear just when payment cannot wait.
Liquidity has several dimensions that the single word can hide. One asset sells quickly in small amounts but moves sharply in price when a large holding is offered. Another has a narrow quoted spread but few standing buyers. A third is readily accepted as collateral by one lender and refused by another. The questions are therefore concrete: how much can be exchanged, how soon, at what cost, and with what uncertainty about the proceeds? None is answered merely by naming the asset safe. A claim that will certainly pay 100 next year can still fetch less than 100 today because time has a price, and it may fetch less again if the holder must sell immediately into a thin market. Safety of final payment and readiness for present payment are related qualities, not identical ones.1
Money occupies the privileged position of being the accepted payment itself within a particular monetary arrangement. A bank deposit can be transferred through that arrangement without its owner first negotiating a market sale of the deposit at a changing price. Behind this everyday convenience lie the bank's obligations and the settlement relations between banks, described in the Bank of England's account of currency, deposits, and reserves. The privilege is not absolute across every place and circumstance: a balance in one currency may require conversion to settle a debt in another, and an inaccessible account cannot pay the grocer merely because its statement is sound. Moneyness belongs to a claim together with the institutions and counterparties that accept it. It is a practical capacity, not a substance discoverable inside the asset.2
A simple comparison shows what that capacity is worth. Suppose two claims each pay 100 on the same date, with the same credit risk, but one can be sold today for 99 while the other requires a hurried seller to accept 94. For that sale the less liquid claim yields five fewer units of usable money. A holder who expects to need immediate payment may rationally prefer the first even if its ordinary expected return is lower. Another who can reliably wait may accept the second. The conditions matter: comparable maturity and credit risk are needed to isolate liquidity, and the holder's freedom to wait cannot be assumed merely because waiting is imaginable. Payroll, margin demands, and household bills can make the sale urgent. The recovered essay's price of immediacy is real, but the ability to decline it is unevenly distributed.3
Pledging an asset can turn it into spendable funds without selling it, but that route has its own boundary. Let a lender accept a bond worth 100 with a 5% haircut, advancing 95 against it. If the haircut becomes 20%, the same market value supports only 80 of borrowing. A borrower seeking to maintain the old advance must find another fifteen units or additional acceptable collateral. No default on the bond is required for this funding need to appear. The earlier Liquidity's warning about the storm reaches beyond the posted spread: a holding may retain much of its eventual value while the arrangements that once let it finance today's payments grow less accommodating. Market liquidity and funding liquidity can thus reinforce one another without being the same thing.4
The danger becomes collective when many holders rely upon the same exit. One investor can plan to sell to another; all cannot assume that everyone else will be a willing buyer at the old price while they sell together. An illustrative market offering to buy ten units at 100 and the next ten at 90 pays a seller of twenty units 1,900, an average of 95, although the first displayed bid was 100. The example is a small order book, not a prediction of a crisis. It exposes the gap between the liquidity of a marginal trade and that of a whole position. Institutions that promise immediate payment against assets sold only with delay must manage that gap. A backstop may help bridge it, but its terms determine which claims gain public support and which losses remain private.5
The spectrum of moneyness is therefore a spectrum of usable promises, assets, and arrangements, not a ladder on which every instrument occupies a permanent rung. A liquid security can become harder to sell; a deposit can be a routine payment medium because a network of settlement and support makes its nominal amount usable; a valuable building can remain wealth without becoming today's wages. The volume began with the difficulty of finding the right exchange and ends with the institutions that let exchange proceed before every asset has found its final owner. What makes a promise spend is the confidence, machinery, and capacity behind its passage. The Tax follows, asking how the state takes a share of what the economy produces. Before it can take that share, this volume has shown, there must be a workable way to count, claim, and pay it.