Money-Market Instruments and Conventions

Introduction

The money market is the part of the financial system in which participants borrow, lend, invest, and manage liquidity over short maturities, normally from overnight to one year. It supports payment systems, government financing, bank treasury operations, corporate working-capital needs, and the implementation of monetary policy. In investment banking, understanding money-market instruments requires more than identifying their legal form. A dealer must also understand quotation conventions, day-count methods, discounting, settlement, collateral, credit risk, and the relationship between quoted rates and economically comparable yields.

Money-market instruments are usually high-quality and relatively liquid, but they are not risk-free. Their risks include issuer default, counterparty failure, liquidity deterioration, collateral shortfall, settlement error, benchmark or basis risk, and legal enforceability risk. Instruments that appear economically similar may produce different prices because they use different day-count conventions or quotation bases.

This chapter explains interbank deposits, Treasury bills, commercial paper, certificates of deposit, repurchase agreements, call money, and bankers’ acceptances. It then develops the conventions needed to price and compare them.

Learning objectives

By the end of this chapter, the reader should be able to:

1. Distinguish the principal money-market instruments and their users.
2. Explain maturity, settlement, value date, and business-day conventions.
3. Calculate prices and proceeds under discount, money-market yield, and bond-equivalent conventions.
4. Convert quoted rates into economically comparable returns, while recognizing the limits of such conversions.
5. Evaluate credit, collateral, liquidity, legal, and operational risks.
6. Apply these concepts to a treasury or investment-banking decision.

1. Architecture of the money market

The principal participants are commercial banks, central banks, governments, investment banks, money-market funds, corporations, insurance companies, pension funds, and securities dealers. Banks use the market to manage reserve balances and temporary funding gaps. Governments issue short-term securities to finance cash deficits. Corporations issue or purchase instruments to manage working capital. Dealers provide market-making, intermediation, and risk-transfer services.

A money-market transaction has several linked dimensions:

• Instrument: the contractual claim, such as a deposit or Treasury bill.
• Term: the period from value date to maturity date.
• Rate basis: discount rate, simple interest yield, annualized return, or repo rate.
• Day-count convention: the number of days treated as elapsed and the denominator used for annualization.
• Settlement convention: the date on which funds and securities are exchanged.
• Credit and collateral structure: whether repayment depends solely on the issuer or is supported by collateral.
• Liquidity: the ease and cost of selling or terminating the position.

The distinction between trade date and value date is essential. The trade date is when parties agree the transaction. The value date is when cash and, where relevant, securities are exchanged. Interest generally begins accruing on the value date, subject to the relevant market convention.

2. Day-count, business-day, and settlement conventions

2.1 Day-count conventions

A day-count convention determines both the numerator and denominator used to calculate accrued interest or a simple money-market return. Common conventions include:

The convention must be stated; otherwise, a numerical rate is incomplete. If a transaction runs for 91 actual days under Actual/360, its year fraction is τ = 91/360, not 91/365.

For a simple interest instrument, interest is commonly calculated as:

where I is interest, P is principal, r is the annualized rate expressed as a decimal, and τ is the day-count fraction. The formula assumes simple, non-compounded interest and is appropriate for many short-term quotations.

2.2 Business-day adjustments

If maturity falls on a weekend or holiday, the contract specifies an adjustment. Under a following convention, the date moves to the next business day. Under preceding, it moves to the previous business day. Under modified following, it moves forward unless doing so changes the calendar month, in which case it moves backward. The applicable convention may alter the number of interest-bearing days and therefore the settlement amount.

2.3 Settlement conventions

Settlement may be same day, next business day, or two business days after trade date. Government securities often use standardized settlement cycles, while deposits may settle on the same day or next day. A dealer must confirm cut-off times, payment instructions, eligible collateral, holidays in all relevant jurisdictions, and whether the maturity date itself is included in the accrual period.

A failed settlement creates replacement-cost, liquidity, and operational risk. Straight-through processing, independent confirmation, and reconciliation between trade capture and payment systems are therefore controls rather than administrative conveniences.

3. Principal money-market instruments

3.1 Interbank deposits

An interbank deposit is an unsecured placement by one bank with another for a specified term. It may be overnight, tomorrow-next, spot-next, or term-dated. The lending bank receives principal and interest at maturity; the borrowing bank receives funding without pledging collateral.

Interbank deposits are commonly quoted as annualized simple rates using Actual/360, although local conventions differ. For a deposit principal P, rate r, and fraction τ, maturity proceeds are:

The lender’s primary risk is the borrower’s creditworthiness. Because the claim is unsecured, the rate normally incorporates the borrower’s credit and liquidity premium. The instrument is flexible and operationally simple, but it may be less liquid than a standardized security.

Example. A bank places $20,000,000 for 45 days at 5.20% Actual/360. The proceeds are:

A = 20,000,000 × (1 + 0.052 × 45/360)

A = $20,130,000.

The interest is $130,000. This calculation assumes no fees, no early termination, and repayment at maturity.

3.2 Treasury bills

Treasury bills are short-term government obligations issued at a discount and redeemed at face value. They normally have no periodic coupon. The investor’s return is embedded in the difference between purchase price and redemption value.

Under a simple discount quotation, the price is:

where F is face value, d is the annualized discount rate, and τ is the applicable day-count fraction. The discount amount is F − P. This formula assumes a discount quote based on face value, not on invested funds.

Example. A 91-day Treasury bill with face value $10,000,000 is quoted at a 4.80% discount rate using Actual/360:

P = 10,000,000 × (1 − 0.048 × 91/360)

P = $9,878,666.67.

The investor pays $9,878,666.67 and receives $10,000,000 at maturity. The holding-period return on funds invested is:

Thus, h ≈ 0.012282, or approximately 1.2282% for 91 days. The simple annualized money-market yield on the purchase price is:

where D is actual days. Here, y ≈ 4.859%. The discount rate of 4.80% is lower because it divides the discount by face value rather than purchase price.

3.3 Commercial paper

Commercial paper is a short-term promissory note issued by a corporation or financial institution, generally to finance inventories, receivables, payroll, or other working-capital requirements. It may be issued at a discount or on an interest-bearing basis.

Important features include issuer credit quality, maturity concentration, back-up liquidity facilities, dealer distribution, investor eligibility, and programme documentation. Commercial paper is usually unsecured, although asset-backed commercial paper may be supported by a pool of receivables and liquidity or credit enhancement.

For a discount issue, the same structural pricing formula may apply:

However, a commercial-paper quotation can use a 360-day or 365-day basis, and the legal documentation governs. Investors should not infer that two notes with identical discount rates have identical returns unless face value, price, maturity, and day-count basis are also identical.

3.4 Certificates of deposit

A negotiable certificate of deposit is a time deposit evidenced by a transferable instrument. The issuing bank promises to pay principal and interest at maturity. Unlike a conventional non-negotiable deposit, a negotiable CD can generally be sold in a secondary market, subject to liquidity and market conditions.

CDs may be quoted on a simple interest basis:

or issued at a discount. The investor evaluates the issuing bank’s credit risk, deposit-insurance treatment, liquidity, minimum denomination, call or put features, and settlement terms. A negotiable CD is not automatically liquid merely because it is transferable; secondary-market depth can disappear during stress.

3.5 Repurchase agreements

A repurchase agreement, or repo, is economically a secured loan structured as a sale of securities with an agreement to repurchase them later at a higher price. The party receiving cash is the cash borrower or repo seller; the party providing cash is the cash lender or repo buyer.

The repurchase price under simple repo interest is:

where C is the cash advanced, r_repo is the repo rate, and τ is the repo day-count fraction. If securities have market value V and the haircut is h, the cash advanced may be:

The haircut protects the cash lender against collateral-price declines, liquidation costs, and timing risk. Repo risk nevertheless includes collateral valuation risk, margin-call risk, counterparty default, legal characterization risk, and settlement risk. A master agreement, typically supported by close-out netting provisions, specifies margining, substitution, eligible collateral, and default remedies.

Example. A dealer delivers securities valued at $50,000,000 with a 2% haircut and borrows for 30 days at 5.00% Actual/360. Cash advanced is $49,000,000. Repurchase price is:

R = 49,000,000 × (1 + 0.05 × 30/360) = $49,204,166.67.

The financing cost is $204,166.67. The collateral value exceeds the cash exposure initially, but the dealer may be required to provide additional collateral if its market value falls.

3.6 Call money

Call money is very short-term borrowing or lending, often overnight or withdrawable at short notice. In some markets, “call” refers to funds repayable on demand, while “notice money” refers to funds repayable after a stated notice period. The terminology is jurisdiction-specific.

Call-money rates are sensitive to reserve conditions, payment flows, central-bank operations, tax dates, and market stress. Although the maturity is short, volatility can be high. A treasury desk must distinguish an overnight rate from a term rate and must not assume that an overnight rate can be rolled over indefinitely at the same level.

3.7 Bankers’ acceptances

A banker’s acceptance is a time draft accepted by a bank, creating the bank’s obligation to pay the stated amount at maturity. It is commonly associated with trade finance, particularly shipments or transactions involving documentary credit. Acceptance by a bank can improve marketability because the investor assesses the accepting bank in addition to the underlying commercial transaction.

Bankers’ acceptances can trade at a discount. Their risk analysis includes the accepting bank, drawer, underlying trade, documentation, sanctions and anti-money-laundering controls, and the enforceability of the acceptance. The instrument has declined in importance in some markets as electronic trade finance and direct bank credit have expanded, but it remains relevant in particular jurisdictions and commodities sectors.

4. Discount rates, yields, and comparability

A central professional skill is distinguishing a quotation from an economic return. Three common measures are:

1. Discount rate: discount divided by face value and annualized.
2. Money-market yield: return divided by purchase price and annualized on a specified day-count basis.
3. Effective annual yield: the annualized compound return implied by the holding-period return.

For a security purchased at price P and redeemed at F after D days, the money-market yield on a 360-day basis is:

The effective annual yield, assuming reinvestment at the same holding-period return, is:

The exponent is a convention for annualization and does not guarantee that reinvestment is possible. If the market uses 365 days, replace 360 consistently. These yields are comparable only after adjusting for day-count, fees, taxes, settlement timing, and embedded options.

For a discount quote d, conversion to a simple purchase-price yield on the same 360-day basis is:

This follows by substituting P = F(1 − dD/360) into the yield formula. It is valid for a simple discount instrument with no fees and a single payment at maturity.

5. Valuation and risk framework

A professional comparison should use a cash-flow map rather than rate labels alone. Identify the cash paid, cash received, dates, collateral movements, fees, and contingencies. Then assess:

• Credit risk: probability and loss severity of issuer or counterparty default.
• Liquidity risk: cost and time required to sell or fund the position.
• Market risk: rate movements affecting mark-to-market value.
• Basis risk: mismatch between the instrument’s rate and the institution’s funding or hedging rate.
• Settlement risk: one party performs while the other does not.
• Legal risk: uncertainty over netting, collateral ownership, insolvency treatment, or documentation.
• Operational risk: errors in confirmations, payment instructions, collateral calls, or maturity processing.
• Concentration risk: excessive exposure to one issuer, sector, country, or maturity date.

Liquidity-adjusted yield is often more useful than headline yield. A slightly higher-yielding unsecured commercial paper position may be inferior to a lower-yielding Treasury bill if the investor requires reliable liquidity under stress.

6. Applied case: a bank treasury funding decision

Background

This illustrative case concerns Meridian Bank, which has $100 million of surplus cash for 30 days. Its treasury desk is considering three placements:

• a 30-day unsecured interbank deposit at 5.10% Actual/360;
• a 30-day Treasury bill yielding 4.85% on a purchase-price money-market basis;
• a 30-day repo secured by high-quality government securities at 4.95% Actual/360, with a 2% haircut.

Assume the bank’s policy assigns a material credit limit to unsecured exposures and requires daily collateral valuation for repo.

Problem

The highest quoted rate is not automatically the best investment. The desk must compare return, credit exposure, collateral, liquidity, operational burden, and the effect of the haircut.

Analysis

For the interbank deposit:

Interest = 100,000,000 × 0.051 × 30/360 = $425,000.

For the Treasury bill, using the stated yield on purchase price, the investment amount is $100 million and proceeds are:

Proceeds = 100,000,000 × (1 + 0.0485 × 30/360) = $100,404,166.67.

The return is $404,166.67. The investment is exposed primarily to sovereign, settlement, and market-liquidity considerations, subject to the relevant jurisdiction.

For repo, the stated $100 million is cash advanced. The lender receives:

Repayment = 100,000,000 × (1 + 0.0495 × 30/360) = $100,412,500.

The return is $412,500, and collateral with market value of at least approximately:

Collateral value = 100,000,000 ÷ (1 − 0.02) = $102,040,816.33

is required if the 2% haircut is defined as cash divided by collateral value. The repo provides collateral protection but requires margin monitoring and legally robust documentation.

Approach and solution

Meridian should first confirm that all rates use the same day-count basis and that the Treasury-bill quote is genuinely a purchase-price yield. It should then apply counterparty limits, evaluate collateral eligibility, and consider whether operational staff can monitor margin calls. If the interbank counterparty is highly rated and within limits, the deposit offers the greatest stated return. If preservation of liquidity and credit protection are priorities, repo may be preferred despite its operational requirements. The Treasury bill may be selected where balance-sheet simplicity and market liquidity outweigh the modest yield difference.

Outcome and learning points

The case demonstrates that rate ranking is only the first step. The economically relevant decision is a risk-adjusted, convention-consistent comparison. A treasury committee should document assumptions, approve limits before trading, and record why the selected instrument fits the institution’s liquidity and risk appetite.

7. Regulation, governance, and technology

Money-market activity is governed by securities, banking, payment-system, collateral, insolvency, market-conduct, and anti-money-laundering rules. Dealers must follow approved counterparties and limits, maintain complete confirmations, observe sanctions controls, and avoid misleading rate presentation. Benchmark manipulation, false marking, and misuse of confidential client information are serious conduct risks.

Central clearing may reduce bilateral counterparty exposure in selected repo markets, but it introduces margin, default-fund, liquidity, and concentration considerations. Electronic trading and automated collateral platforms improve processing speed, yet model and cyber risk remain. Artificial intelligence can assist with cash-flow forecasting, anomaly detection, document review, and collateral optimization. It should not replace human approval of unusual trades, override credit limits, or make opaque decisions without validation, explainability, access controls, and audit trails.

Best practice includes using standardized master agreements, independent price verification, pre-trade eligibility checks, automated holiday calendars, maker-checker payment controls, daily reconciliation, stress testing, and documented escalation procedures. Stress scenarios should include counterparty downgrade, collateral price gaps, inability to roll commercial paper, payment-system disruption, and simultaneous margin calls.

Chapter Summary

Money-market instruments provide short-term funding and investment channels but differ substantially in credit structure, liquidity, collateral, legal form, and quotation method. Interbank deposits and CDs are generally bank-credit exposures; commercial paper and bankers’ acceptances provide corporate or trade-related financing; Treasury bills are discounted sovereign instruments; repos are collateralized financing transactions; and call money addresses very short-term liquidity needs.

Day-count and settlement conventions determine the cash flows underlying quoted rates. A discount rate is not the same as a yield on invested funds. Prices, simple money-market yields, and effective annual yields must be calculated using consistent assumptions. Professional analysis therefore requires a complete cash-flow map, explicit conventions, and assessment of credit, liquidity, market, legal, collateral, settlement, and operational risks.

Key Terms

Day-count convention: Rule specifying how elapsed days and annualization are calculated.

Value date: Date on which funds and securities are exchanged.

Interbank deposit: Unsecured short-term deposit placed with another bank.

Treasury bill: Short-term government obligation usually issued below face value.

Discount rate: Annualized discount expressed as a proportion of face value.

Commercial paper: Short-term corporate or financial-institution promissory note.

Certificate of deposit: Time deposit evidenced by an instrument, often negotiable.

Repo: Secured financing structured as a sale and repurchase of securities.

Haircut: Reduction applied to collateral value when determining cash advanced.

Call money: Very short-term funds repayable on demand or at short notice.

Banker’s acceptance: Time draft accepted and guaranteed for payment by a bank.

Money-market yield: Annualized return calculated on funds invested.

Effective annual yield: Compound annualized return implied by a holding-period return.

Settlement risk: Risk that one party performs while the other fails to perform.

Liquidity risk: Risk of loss or delay when selling or funding an instrument.

Basis risk: Risk arising from mismatch between relevant interest-rate bases.

Master agreement: Standard legal contract governing recurring transactions.

Collateral margining: Process of adjusting collateral to maintain protection.

Review Questions

Short Answer Questions

1. Why is a day-count convention necessary for a money-market quotation?
2. Distinguish a discount rate from a money-market yield.
3. What is the economic purpose of a repo haircut?
4. How does a negotiable certificate of deposit differ from an ordinary time deposit?
5. Identify two risks associated with bankers’ acceptances.

Long Answer Questions

1. Explain the structure, users, and principal risks of interbank deposits, commercial paper, and certificates of deposit.
2. Describe how Treasury bills are priced under a simple discount convention and explain why their discount rate differs from their investment yield.
3. Analyze the legal, collateral, liquidity, and operational dimensions of repurchase agreements.
4. Compare call money and term interbank deposits as instruments of bank liquidity management.
5. Explain how day-count, settlement, and business-day conventions affect the valuation and comparison of money-market instruments.

Analytical / Application Questions

1. A 90-day bill with face value $5,000,000 is quoted at a 4.50% discount rate using Actual/360. Calculate its purchase price and approximate money-market yield on the purchase price.
2. A bank can place funds in an unsecured deposit or a repo with a lower rate. Construct a decision framework that incorporates return, counterparty exposure, haircut, collateral volatility, liquidity, and operational capacity.
3. Two instruments offer the same annualized rate but use Actual/360 and Actual/365 respectively. Explain why their cash returns may differ and specify the information required before selecting between them.

Multiple Choice Questions with Answers

Question 1

Under a simple interest convention, what is the maturity amount for principal P, annual rate r, and year fraction τ?

A. P × (1 − rτ)

B. P × (1 + rτ)

C. P ÷ (1 + rτ)

D. P × r ÷ τ

Correct Answer: B. P × (1 + rτ)

Question 2

A Treasury bill discount rate is calculated using which base?

A. Face value

B. Purchase price only

C. Collateral value

D. Coupon amount

Correct Answer: A. Face value

Question 3

A 90-day deposit of $10,000,000 earns 4.00% Actual/360. What is the interest?

A. $10,000

B. $40,000

C. $100,000

D. $1,000,000

Correct Answer: B. $40,000

Question 4

What is the principal protection mechanism in a conventional repo?

A. An equity dividend

B. Collateral and a haircut

C. A floating coupon only

D. Deposit insurance in every case

Correct Answer: B. Collateral and a haircut

Question 5

Which instrument is normally an unsecured corporate short-term promissory note?

A. Commercial paper

B. Treasury bill

C. Repo

D. Collateralized loan obligation

Correct Answer: A. Commercial paper

Question 6

If a bill is bought at P and redeemed at F after D days, which expression gives a 360-day money-market yield?

A. (F − P) ÷ F × D ÷ 360

B. (F − P) ÷ P × 360 ÷ D

C. P ÷ F × 360 ÷ D

D. (F + P) ÷ P × D ÷ 360

Correct Answer: B. (F − P) ÷ P × 360 ÷ D

Question 7

What does the value date identify?

A. The date the instrument was first advertised

B. The date funds and securities are exchanged

C. The date a credit rating is issued

D. The date a trade is reported publicly

Correct Answer: B. The date funds and securities are exchanged

Question 8

Which risk is especially associated with an unsecured interbank deposit?

A. Issuer or counterparty default risk

B. Collateral substitution risk only

C. Equity dilution risk

D. Commodity delivery risk only

Correct Answer: A. Issuer or counterparty default risk

Question 9

A banker’s acceptance is primarily what type of claim?

A. A bank-accepted time draft

B. A perpetual preferred share

C. A central-bank reserve balance

D. A floating-rate government bond

Correct Answer: A. A bank-accepted time draft

Question 10

What does a 2% repo haircut generally do?

A. Increases cash advanced above collateral value

B. Reduces cash advanced relative to collateral value

C. Eliminates all counterparty risk

D. Converts the repo into unsecured lending

Correct Answer: B. Reduces cash advanced relative to collateral value