science

Mark to model

Mark to model 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 Mark to model rather than just read about it. In short: Mark-to-Model refers to the practice of pricing a position or portfolio at prices determined by financial models, in contrast to allowing the market to determine the price. Often the use of models is necessary where a market for the financial product is not available, such as with complex financial instruments.

Key takeaways

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

Reference excerpt

Mark-to-Model refers to the practice of pricing a position or portfolio at prices determined by financial models, in contrast to allowing the market to determine the price. Often the use of models is necessary where a market for the financial product is not available, such as with complex financial instruments. One shortcoming of Mark-to-Model is that it gives an artificial illusion of liquidity, and the actual price of the product depends on the accuracy of the financial models used to estimate the price.

On the other hand it is argued that Asset managers and Custodians have a real problem valuing illiquid assets in their portfolios even though many of these assets are perfectly sound and the asset manager has no intention of selling them. Assets should be valued at mark to market prices as required by the Basel rules. However mark to market prices should not be used in isolation, but rather compared to model prices to test their validity. Models should be improved to take into account the greater amount of market data available. New methods and new data are available to help improve models and these should be used. In the end all prices start off from a model.

Hedge Funds Hedge funds may use mark-to-model for the illiquid portion of their book. Another shortcoming of mark-to-model is that even if the pricing models are accurate during typical market conditions there can be periods of market stress and illiquidity where the price of less liquid securities declines significantly, for instance through the widening of their bid-ask spread. The failure of Long-Term Capital Management, in 1998, is a well-known example where the markets were shaken by the Russian financial crisis, causing the price of corporate bonds and treasury bonds to get out of line for a period longer than expected by the LTCM's models. This situation caused the hedge fund to melt down, and required a Fed bailout to prevent the toxicity from spilling into other financial markets.

Enron Collapse The collapse of Enron is a well-known example of the risks and abuses of Mark-to-Model pricing of Futures contracts. Many of Enron's contracts were difficult to value since these products were not publicly traded, thus computer models were used to generate prices. When Enron's profits began to fall with increased competition, accounts manipulated the mark-to-market models to put a positive spin on Enron's earnings.

Criticism In 2003, Warren Buffett criticised mark-to-model pricing techniques in the derivatives market for bringing on "large scale mischief" and degenerating into "mark-to-myth".

See also Arbitrage-Free Model Mark to market Model risk

References

SEC gives banks more leeway on mark-to-market Level 1, Level 2, Level 3 Assets

Worked examples

Example 1 — a first encounter with Mark to model

Start with the simplest possible case. Write down what Mark to model 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 Mark to model 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 Mark to model 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 Mark to model

In research: Mark to model 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 Mark to model 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: Mark to model is common in secondary-school and first-year university syllabi. It links to neighbouring topics Derivatives (finance), Enron, Financial models, so understanding it makes those chapters shorter.
In everyday life: Look for Mark to model 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 Mark to model in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Mark to model 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 Mark to model out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Mark to model in simple terms?

Why does Mark to model 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 Mark to model?

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 Mark to model.