What it means
Governments create agencies to do specific jobs, such as supporting home lending, farm credit or student finance, and those agencies raise money by selling bonds. Some of these issuers carry an explicit government guarantee, while others carry only an implied one, which is a market assumption rather than a legal promise.
That distinction is the single most important thing to check before buying. Because investors treat agency paper as very high quality, it trades at a small spread over government bonds.
The spread is usually measured in basis points, where one basis point is one hundredth of 1%. A spread of 30 to 60 basis points is common in calm markets and widens when investors rush towards the very safest assets.
Agency securities come in several shapes. Plain bullet bonds pay a fixed coupon and repay the face amount at maturity; callable agency bonds let the issuer repay early if interest rates fall; and mortgage-backed agency securities pass through the repayments made by thousands of individual homeowners.
The last group behaves very differently because borrowers repay early when rates drop, shortening the life of the investment exactly when reinvestment is least attractive. Corporate treasurers hold agency securities in short-term investment portfolios because they combine decent liquidity with a modest yield pickup.
Pension funds and insurers hold longer-dated agency paper to match long liabilities. In both cases the appeal is the same: a small step up in return for what feels like a very small step up in risk.
The nuance most non-specialists miss is that credit risk is not the only risk in the instrument. Interest rate risk, call risk and, for mortgage-backed paper, prepayment risk can all move the value of an agency security well before any question of default arises.
In practice
Real-world examples.
Example
A mid-sized engineering group holds $6,000,000 of surplus cash ahead of a plant build. The treasurer places $4,000,000 into short-dated agency bonds maturing in eleven months, picking up around 35 basis points over Treasury bills while keeping the money easy to sell if the build starts early.
Example
A regional insurer needs assets that will still be paying in fifteen years to match its long-tail claims. It buys long-dated agency paper rather than corporate bonds because the credit quality is close to government level and the duration is a good match.
Example
A money market fund is restricted by its rules to government and agency issuers only. When corporate credit spreads widen during a wobble in markets, the fund cannot take advantage, but it also avoids the losses, which is exactly the trade-off its investors signed up for.
Formula
Calculation
Current yield = annual coupon income / price paid, and spread = agency yield - government bond yield of the same maturity.
A corporate treasurer buys an agency bond with a face value of $100,000, a 4.5% coupon paid twice a year, at a price of 98.50 per 100 of face value. The cash outlay is $100,000 x 0.9850 = $98,500, and each half-yearly coupon is $100,000 x 0.045 / 2 = $2,250, so annual coupon income is $4,500.
Current yield is $4,500 / $98,500 = 0.04569, or 4.57% when rounded to two decimal places. If a government bond of the same maturity yields 4.20%, the pickup is 4.57% - 4.20% = 0.37%, which the market would quote as 37 basis points. On the $98,500 invested, that spread is worth roughly $98,500 x 0.0037 = $364 of extra income a year, which is the compensation for accepting agency rather than direct government credit.Case study
Seen in the real world.
Harbourline Freight is an illustrative, fictional logistics company that had built up $22,000,000 of cash while waiting on a port concession decision. The board wanted the money safe but was unhappy earning almost nothing on an overnight deposit account.
The treasurer split the balance. She kept $7,000,000 in an instant access deposit, placed $9,000,000 into agency bonds maturing inside twelve months and $6,000,000 into agency bonds maturing in two to three years. The blended yield across the portfolio came out at about 4.4% against 3.9% on the deposit account, worth roughly $110,000 a year on the $22,000,000.
The lesson in this fictional case came six months later. The concession decision slipped, and Harbourline had to sell part of the two to three year block early. Rates had risen, so the bonds sold slightly below cost and a chunk of the extra income was given back. The treasurer had matched credit quality to the board's appetite but had underestimated how quickly the cash might be needed, which is the classic mistake with agency securities.
Watch out
Common mistakes.
- Assuming every agency security carries a full government guarantee. Some issuers are explicitly backed and some are only implicitly supported, and the difference matters most in exactly the conditions where you would rely on it.
- Judging an agency bond purely on its credit rating. A highly rated bond can still lose value if interest rates rise, if it is called early or if underlying mortgages repay faster than expected.
- Treating agency paper as interchangeable with cash. It is liquid, not instant, and selling before maturity can crystallise a loss if rates have moved against you.
Questions
People also ask.
What is the difference between an agency security and a Treasury bond?
A Treasury bond is a direct obligation of the government itself, while an agency security is issued by a separate body that may or may not carry a formal government guarantee.
Why would a company buy agency bonds rather than corporate bonds?
Because the credit risk is far lower for only a modest reduction in yield, which suits money that must be there when it is needed.
What is call risk on an agency bond?
It is the risk that the issuer repays the bond early when interest rates fall, leaving the investor to reinvest the proceeds at a lower rate than the coupon it was enjoying.
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