What it means
The bond market has two halves. The primary market is where new debt is sold, by auction for government bonds and through underwriting banks for corporate issues, while the secondary market is where those bonds change hands afterwards, mostly through dealers and electronic platforms rather than a central exchange.
Size is a large part of why it matters. Global bond markets are much bigger than equity markets by value, and because governments fund themselves there, the yields set in the bond market become the reference rate for mortgages, corporate borrowing and the discount rate used to value almost everything else.
The most watched output is the yield curve, a plot of yields against maturity for the same issuer. Longer maturities normally yield more, and when that relationship reverses, with short rates above long rates, investors read it as a signal that rate cuts and weaker growth are expected.
Corporate bonds are priced off the government curve as a spread. If a ten year government bond yields 4% and a company's ten year bond yields 5.5%, that 1.5 percentage point gap is the credit spread, and it widens when investors turn nervous and narrows when confidence returns.
Even a business that never buys a bond is affected, because this market sets the price of money. A treasurer refinancing a facility, a chief financial officer choosing between debt and equity, and an analyst valuing a project all take their starting point from bond yields, which is why finance teams watch them without ever trading.
In practice
Real-world examples.
Example
A government raises $12,000,000,000 in a bond auction. Demand is weaker than expected, so the bonds clear at a higher yield, and within hours mortgage lenders reprice their fixed rate products upward because their funding costs are tied to those yields.
Example
An insurance company must meet claims falling due over the next thirty years. It buys long dated government bonds specifically because their maturity profile matches the payments it has promised, not because it expects them to be the best performing asset available.
Example
A private equity firm delays a planned acquisition after credit spreads widen by a full percentage point in a month. The debt package that would have cost 7% now costs 8%, and on $300,000,000 of borrowing that is $3,000,000 of extra interest a year, enough to break the return model.
Formula
Calculation
There is no single bond market formula, but the calculation practitioners run most often is the effect of a change in yields on the value of a bond holding:
Approximate change in value = modified duration x change in yield x current value
Worked example. A treasury team holds a $10,000,000 bond portfolio with an average coupon of 4% and a modified duration of 6.0, so expected coupon income for the year is $10,000,000 x 0.04 = $400,000.
Market yields then rise by 0.5 percentage points. The estimated fall in value is 6.0 x 0.5% = 3.0%, and 3.0% of $10,000,000 is $300,000, taking the portfolio value to $9,700,000.
Putting the two together, the total return for the year is $400,000 of income less $300,000 of price loss, a gain of $100,000, or 1% on the starting value. Had duration been 10.0 rather than 6.0, the price fall would have been 10.0 x 0.5% = 5.0%, or $500,000, and the same portfolio would have shown a loss of $100,000 instead.Case study
Seen in the real world.
Belmont Water Utilities is a fictional regulated utility used here as an illustration. It planned to refinance $250,000,000 of maturing debt and had budgeted a 4.5% coupon, based on where comparable utilities had issued three months earlier.
Between the board approving the plan and the issue reaching the market, government yields rose by 0.6 percentage points and credit spreads for the sector widened by a further 0.4, so the achievable coupon became 5.5%. On $250,000,000 that extra 1.0 percentage point is $2,500,000 a year of additional interest against the budget, or $25,000,000 across a ten year term.
In the illustrative outcome, Belmont issued $150,000,000 immediately to cover the near term maturity and used a short bank facility for the balance, planning to return to the market once conditions settled. The treasurer's report noted that the company had done nothing wrong operationally, and that the price of its money had simply changed while it was getting ready to ask for it.
Watch out
Common mistakes.
- Thinking of the bond market as a smaller sideshow to the stock market, when it is larger by value and sets the interest rates that share valuations depend on.
- Reading a falling bond price as bad news about the issuer, when most price movements are caused by changes in market interest rates rather than by credit quality.
- Assuming bond prices are quoted like share prices, when they are usually quoted per $100 of face value and shown alongside a yield that carries the real information.
Questions
People also ask.
Where is the bond market physically located?
Mostly nowhere visible, because the bulk of trading happens over the counter between dealers and institutions rather than on a public exchange.
What does an inverted yield curve mean?
It means short dated bonds yield more than long dated ones, which is usually read as investors expecting interest rates and economic growth to fall.
Why do bond investors worry so much about inflation?
Because the payments are fixed in cash terms, so higher inflation reduces what those payments buy and pushes yields up, which lowers the price of bonds already in issue.
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