science

Overnight rate

Overnight rate is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Overnight rate rather than just read about it. In short: The overnight rate is generally the interest rate that large banks use to borrow and lend from one another in the overnight market. In some countries (the United States, for example), the overnight rate may be the rate targeted by the central bank to influence monetary policy.

Key takeaways

Overnight rate belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Overnight rate to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Overnight rate from memory before moving on to harder problems.

Reference excerpt

The overnight rate is generally the interest rate that large banks use to borrow and lend from one another in the overnight market. In some countries (the United States, for example), the overnight rate may be the rate targeted by the central bank to influence monetary policy. In most countries, the central bank is also a participant on the overnight lending market, and will lend or borrow money to some group of banks. There may be a published overnight rate that represents an average of the rates at which banks lend to each other; certain types of overnight operations may be limited to qualified banks. The precise name of the overnight rate will vary from country to country.

Background Throughout the course of a day, banks will transfer money to each other, to foreign banks, to large clients, and other counterparties on behalf of clients or on their own account. At the end of each working day, a bank may have a surplus or shortage of funds (or a shortage or excess reserves in fractional reserve banking). Banks that have surplus funds or excess reserves may lend them (often at a multiple of their legal reserve ratio, if any) or deposit them with other banks, who borrow from them. The overnight rate is the amount paid to the bank lending the funds. Banks will also choose to borrow or lend for longer periods of time, depending on their projected needs and opportunities to use money elsewhere. Most central banks will announce the overnight rate once a month. In Canada, for example, the Bank of Canada sets a target bandwidth for the overnight rate each month of +/- 0.25% around its target overnight rate: the Bank of Canada does not interfere in the overnight market so long as the overnight rate stays within its target band, but the Bank will use its reserves to lend or borrow in the overnight market to ensure that the overnight rate stays within its announced bandwidth.

Measure of liquidity Overnight rates are a measure of the liquidity prevailing in the economy. In tight liquidity conditions, overnight rates shoot up. Overnight rates may also shoot up due to lack of confidence amongst banks, as was observed in the liquidity crunch of 2008. In order to measure liquidity situation, the spread between risk-free rates and overnight rates is considered. The TED spread is a liquidity indicator for the U.S., which is the difference between LIBOR and Treasury bills.

See also Bank rate Interbank lending market Overnight indexed swap

References

Worked examples

Example 1 — a first encounter with Overnight rate

Start with the simplest possible case. Write down what Overnight rate claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Overnight rate before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Overnight rate ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Overnight rate

In research: Overnight rate appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Overnight rate in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Overnight rate is common in secondary-school and first-year university syllabi. It links to neighbouring topics Banking, Interest rates, so understanding it makes those chapters shorter.
In everyday life: Look for Overnight rate outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Overnight rate in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Overnight rate means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Overnight rate out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Overnight rate in simple terms?

Why does Overnight rate matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Overnight rate?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Overnight rate.