CFA Level II Exam · The Term Structure and Interest Rate Dynamics

Traditional Theories of the Term Structure of Interest Rates

Updated 7 October 2026 · Fact-checked

Traditional term structure theories explain why yield curves slope up, down or flat. Pure expectations says forward rates are unbiased forecasts of future spot rates. Liquidity preference adds a term premium. Segmented markets says each maturity has its own supply and demand. Preferred habitat allows investors to switch maturities for enough yield.

Understand Traditional Theories of the Term Structure

A yield curve plots yields against maturity. The traditional theories give different reasons for its shape. You must be able to match a vignette statement to the right theory.

Pure (unbiased) expectations theory: the forward rate equals the expected future spot rate. Investors are risk neutral. A long-term rate is an average of the expected short rates. An upward slope means the market expects short rates to rise. A downward slope means it expects them to fall. Risk is ignored, so there is no premium for holding long bonds.

Local expectations theory: a weaker version. It says the expected return over a short holding period is the risk-free rate for bonds of all maturities. It holds for short periods only. Over longer horizons, returns can differ by maturity. Do not confuse it with pure expectations. Pure expectations claims equal returns over any horizon.

Liquidity preference theory: investors are risk averse. Long bonds have more interest rate risk, so investors demand a liquidity (term) premium that rises with maturity. Forward rate = expected future spot rate + liquidity premium. So forward rates are upward-biased estimates of future spot rates. The curve can slope up even if short rates are expected to stay flat. A downward-sloping curve then signals that expected short rates are falling by more than the premium.

Segmented markets theory: investors and borrowers have fixed maturity needs, such as a pension fund matching long liabilities. Each maturity segment has its own supply and demand, and rates are set within it. Expectations and risk premiums across maturities play no role. Preferred habitat theory: investors have a preferred maturity but will move to other maturities if the extra yield is enough. So yields reflect expected short rates plus a term premium that can be positive or negative, depending on supply and demand. It sits between segmented markets and liquidity preference.

Key formulas to remember

Pure expectations: Forward rate = expected future spot rate; Two-year yield: (1 + S2)² = (1 + S1)(1 + E[S1 one year ahead]). No risk premium.
Liquidity preference: Forward rate = E[future spot rate] + liquidity premium; Premium is positive and generally increases with maturity. Forward rates overstate expected spot rates.
Preferred habitat: Forward rate = E[future spot rate] + term premium; Premium reflects supply and demand by maturity. It can be positive or negative.
Local expectations: Expected one-period return = risk-free rate for all maturities; Applies over short holding periods only.

How to solve Traditional Theories of the Term Structure questions

Use this routine for any theory question in an item set.

1Read the question stem and find what is being asked: shape explanation, forward rate bias, or theory identification.
2Underline in the vignette words about risk, premium, maturity needs, or expectations of rate changes.
3Ask first: is there any premium for maturity? If none, it is pure or local expectations.
4If a premium exists and rises steadily with maturity, choose liquidity preference.
5If investors or borrowers are tied to one maturity and no switching occurs, choose segmented markets.
6If investors switch maturities for compensation, and premiums vary in sign or size, choose preferred habitat.
7For numbers, subtract the premium from the forward rate to get the expected spot rate, or add it to go the other way.
8Check that your conclusion on slope matches the theory's logic.

Quickest way: Premium and switching test

When to use it: Use when a vignette describes investor behaviour and asks you to name the theory or explain the curve.

No premium and rate expectations drive everything: pure expectations.
Premium grows with maturity because of risk aversion: liquidity preference.
No link between maturities, separate markets: segmented markets.
Maturity preference but switching for yield: preferred habitat.
Short holding period equal returns only: local expectations.

Common mistakes in Traditional Theories of the Term Structure

Saying pure expectations and local expectations are the same.
Both use expected rates and no risk premium in the headline.
Fix: Local expectations only gives equal expected returns over a short period. Pure expectations gives equal returns over any horizon.
Treating an upward-sloping curve as proof the market expects higher short rates.
That is true only under pure expectations.
Fix: Under liquidity preference or preferred habitat, part of the slope is premium. Check which theory applies.
Taking the forward rate as the expected spot rate under liquidity preference.
Students carry over the pure expectations rule.
Fix: Subtract the liquidity premium from the forward rate to get the expected spot rate.
Saying preferred habitat requires a positive premium that always rises with maturity.
It is mixed up with liquidity preference.
Fix: Under preferred habitat the premium reflects supply and demand and can be positive or negative.
Saying segmented markets lets investors switch maturities when yields differ.
Confusion with preferred habitat.
Fix: Segmented markets has no switching. Rates are set within each maturity segment alone.

Worked examples

Example 1

Vignette: An analyst observes a one-year spot rate of 3.0% and a one-year forward rate, one year ahead, of 4.2%. Under liquidity preference theory, the analyst estimates the liquidity premium for that forward period at 0.5%. Questions: (1) What is the expected one-year spot rate one year from now? (2) What would it be under pure expectations? (3) Which theory predicts the forward rate is an upward-biased predictor?

Show the solution

Liquidity preference: forward = expected spot + premium.
Expected spot = 4.2% − 0.5% = 3.7%.
Pure expectations has no premium, so expected spot = forward = 4.2%.
The forward rate exceeds the expected spot rate only when a positive premium exists, which is liquidity preference.

Answer: (1) 3.7%. (2) 4.2%. (3) Liquidity preference theory.

Example 2

Vignette: A pension fund manager says she buys only 25-year bonds to match her liabilities and would not buy 10-year bonds even at a much higher yield. A second manager says he normally buys 10-year bonds but would hold 20-year bonds if they offered enough extra yield. Questions: (1) Which theory fits the first manager? (2) Which fits the second? (3) Under the second theory, can the term premium be negative?

Show the solution

The first manager will not leave her maturity at any yield, so markets are segmented.
The second manager has a preferred maturity but switches for compensation, so preferred habitat.
In preferred habitat the premium reflects supply and demand by maturity, so it can be positive or negative.

Answer: (1) Segmented markets theory. (2) Preferred habitat theory. (3) Yes, it can be negative.

Exam tips

Match the key words: risk neutral means pure expectations; risk averse with growing premium means liquidity preference; no switching means segmented markets.
Know that liquidity preference makes forward rates upward-biased estimates of future spot rates.
Expect statements asking whether the curve shape implies rate expectations. Check whether the theory allows a premium.
Do the premium arithmetic carefully: forward minus premium gives expected spot.
Local expectations is short-horizon only. Use that single point to separate it from pure expectations.

Traditional Theories of the Term Structure in other exams

The same ground in other exams, if you are preparing for more than one or want another angle on it.

Traditional Theories of the Term Structure: frequently asked questions

What is the difference between expectations theory and liquidity preference theory?

Pure expectations says forward rates are unbiased forecasts of future spot rates, with no premium. Liquidity preference adds a positive premium that grows with maturity because investors dislike interest rate risk.

How does preferred habitat differ from market segmentation?

In market segmentation, investors stay in their maturity segment and do not switch. In preferred habitat, they have a preferred maturity but will move for enough extra yield, so term premiums link the segments.

Why is the yield curve upward sloping according to these theories?

Pure expectations says the market expects short rates to rise. Liquidity preference says investors need a term premium for long bonds. Segmented markets says demand and supply in the long segment push yields higher. Preferred habitat combines expectations and a premium.

What is local expectations theory?

It says that over a short holding period, the expected return on bonds of every maturity equals the risk-free rate. It does not claim the same for long horizons, which is how it differs from pure expectations.