Duration Times Spread (DTS)
Two bonds with the same spread duration don't carry the same spread risk if their spreads are wildly different levels — DTS multiplies duration by spread level to measure risk the way spreads actually move, proportionally.
Prerequisites: Spread Duration, Credit Spreads
Spread duration tells you how much a bond's price moves if its spread widens by one basis point. That works fine for comparing two investment-grade bonds with similar spreads. But a distressed bond trading at a 2,000 basis point spread doesn't move in one-basis-point increments the way a 100 basis point investment-grade bond does — its spread moves in percentage terms, not flat basis points, and ordinary spread duration badly understates its real risk.
Duration times spread (DTS) multiplies a bond's spread duration by its current spread level. It captures the empirical fact that spreads move roughly proportionally to their own level — a bond at 800 basis points tends to move eight times as much, in basis point terms, as one at 100 basis points with the same duration — so DTS is a far better predictor of actual spread risk than duration alone.
The formula and the intuition
In words: take how sensitive the bond's price is to a one-basis-point spread move, and scale it by how wide that spread already is. A high-spread bond gets flagged as riskier even at the same duration, because empirically its spread swings by more basis points in absolute terms when credit conditions shift.
This matters for portfolio construction because it changes which bonds actually drive a portfolio's risk. A portfolio manager comparing two bonds with identical 5-year spread duration — one investment-grade at 100 basis points, one high-yield at 500 basis points — using ordinary duration alone would treat them as equally risky. DTS says the high-yield bond carries five times the spread risk, matching what's actually observed: wide-spread bonds' spreads move by more basis points, in both directions, than tight-spread bonds' do.
Worked example
Bond A: spread duration of 5 years, spread of 100 basis points. Bond B: spread duration of 4 years, spread of 600 basis points.
- Bond A's DTS. .
- Bond B's DTS. .
Even though Bond A has longer duration, Bond B's DTS is nearly five times higher. If overall credit spreads widen by 10% in relative terms (a typical way spread shocks are modeled), Bond A's spread widens by about 10 basis points while Bond B's widens by about 60 basis points — and the price impact, driven by duration times that basis point move, is far larger for Bond B despite its shorter duration.
What this means in practice
Credit portfolio managers use DTS, not plain spread duration, to size positions and set risk budgets, because it tracks how spreads actually behave — proportionally, not in fixed basis-point steps — across the ratings spectrum from investment grade to distressed.
A common mistake is assuming a shorter-duration, wider-spread bond is automatically "less risky" because duration alone looks smaller. DTS corrects for exactly this trap: high-spread names can carry substantially more risk than their duration alone suggests.
Related concepts
Practice in interviews
Further reading
- Ben Dor et al., 'Duration Times Spread: A New Measure of Spread Exposure', Journal of Portfolio Management