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Introduction 

● This presentation introduces the Yield Curve for Treasury 

Nominal Coupon Issues (TNC yield curve). The TNC curve is 

derived from data for Treasury notes and bonds.

● The TNC yield curve uses the methodology developed at Treasury 

for the High Quality Market (HQM) Yield Curve for the Pension 

Protection Act (PPA), and extends this methodology to the 

Treasury market. 

● This presentation discusses basic concepts for understanding and 

using the TNC yield curve, and presents an overview of the curve 

methodology. For links to more detailed documentation and 

technical descriptions, see the last slide.
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TNC Yield Curve Summary 

● A yield curve provides information about a sector of the bond 

market at a point in time. The information includes yields on 

different types of bonds in this sector at various maturities.

● The TNC yield curve provides information on Treasury nominal 

coupon issues, that is, notes and bonds that pay semiannual fixed 

coupons in dollars. The TNC curve includes both on-the-run 

issues (securities most recently issued of each maturity) and 

older off-the-run issues; however, in this presentation, the focus 

is on yields of off-the-run issues.

● The TNC methodology also projects yields beyond 30 years 

maturity out through 100 years maturity. The methodology 

ensures that the projections are consistent with yields before 30 

years maturity and with long-term investment returns available 

in the market.
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The Par Yield Curve 

● One set of information provided by the TNC yield curve is 

the Treasury par yield curve.

● The par yield curve shows for each maturity the yield on a 

Treasury nominal coupon issue of that maturity that is 

selling at par (price excluding accrued interest equals 100).

● The par yield curve provides a picture of the Treasury 

market for coupon issues, and is used for market analysis.
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The Spot Yield Curve 

● Another set of information from the TNC yield curve is the 

Treasury spot yield curve.

● The spot yield curve shows for each maturity the yield on a 

Treasury security without coupons that provides a single 

nominal payment at that maturity. Such a security can be 

called a zero coupon bond. The yields are called spot rates.

● Because the TNC yield curve uses coupon issues, there are 

no actual zero coupon securities in the TNC dataset. 

Therefore, the spot rates are inferred from the TNC par 

yield curve.

● The TNC spot rates are used to discount future cash flows 

to get their present value.
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The Spot Yield Curve, continued 

● For most applications, the TNC curve is used to generate 

spot rates for each maturity at half-year intervals for 

maturities of 1⁄2 year up through 100 years, for a total of 

200 spot rates. The rates are semiannually compounded.

● The TNC yield curve is calculated late in the day for each 

business day, and the monthly TNC spot rate at each 

maturity is the average of rates at that maturity for the 

business days of the month. Quarterly TNC spot rates are 

averages of the three monthly rates at each maturity for 

the quarter.

● Off-the-run TNC spot rates can be interpreted as the riskfree social rates of time preference. Therefore, social 

preference is indifferent between future cash flows and 

their present values discounted by the TNC spot rates.
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Yield Curves for End of March 

● The next two slides contain the TNC off-the-run par and 

spot yield curves for March 31, 2014.

● There are 264 Treasury nominal coupon issues in the 

dataset for this day. The par yield curve in slide 8 includes 

a scatter diagram of the yields of these securities, with onthe-run securities indicated by squares. For this day, 

yields on the on-the-run securities are close to the curve.

● The spot yield curve in slide 9 is derived from the par 

curve, and is projected out to 100 years maturity. The spot 

rate is 3.78 percent at 30 years maturity, and the curve 

continues to rise beyond 30 years maturity reaching 4.12 

percent at 100 years maturity.

● Both yield curves are very smooth without any hump.
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Par Yield Curve

TNC PAR YIELD CURVE

3/31/2014, Percent

On-The-Run Yields

Off-The-Run Yields

Maturity
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TNC SPOT YIELD CURVE

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TNC Yield Curve Methodology 

● Different yield curve methodologies can produce different 

results, which affect discounted cash flows and everything 

else for which the curves are used. Therefore, it was 

essential for Treasury to develop and implement the 

methodology that accurately captures market behavior.

● Moreover, an understanding of the TNC methodology aids 

greatly in the appropriate use of the TNC curve.

● The TNC methodology is the same as the methodology used 

for the HQM corporate bond yield curve with modifications 

for the Treasury market.
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The TNC yield curve methodology contains features and 

capabilities that do not appear in other yield curve 

approaches: 

TNC Methodology Features 

● The TNC methodology combines regression variables with 

the yield curve.

● The methodology projects yields beyond 30 years.

● The methodology makes use of established bond market 

characteristics to generate a stable yield curve that 

captures market movements. 
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TNC Methodology: Regression Variables 

● The TNC methodology has the special capability of combining 

regression variables with the yield curve. The regression 

terms adjust for special features of the market and particular 

attributes of individual bonds.

● The TNC yield curve contains two sets of regression variables. 

The first variable measures the hump in yields that is 

sometimes seen around 20 years maturity.

● The second set of variables is for on-the-run and first off-therun securities, and measures price differences of such 

securities relative to other off-the-run prices. As opposed to 

other approaches, the TNC yield curve includes both on- and 

off-the-run securities in the same model and takes account of 

on-the-run effects.
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TNC Methodology: Projections 

● The TNC methodology projects yields beyond 30 years 

maturity out to 100 years maturity. The projections 

provide discount rates for long-dated cash flows. 

● The methodology ensures that the projections are 

consistent with yields before 30 years maturity and with 

long-term investment returns available in the market. 

● Other yield curve approaches generally stop at 30 years 

maturity and contain no provision for projection. 

Therefore, there is no mechanism in those approaches to 

ensure that yields around 30 years maturity are consistent 

with earlier yields in the dataset. Building the projection 

methodology into the yield curve solves this problem.
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● The TNC methodology is derived from basic hypotheses 

about bond markets. The hypotheses inform the setting of 

the parameters that underpin the TNC yield curve.

● Other yield curve approaches typically use mathematical 

functions that don’t have any foundation in market 

hypotheses.

● Consequently, differences among yield curves given by 

other approaches with different mathematics are arbitrary, 

in that there is no way to choose among them.

TNC Methodology: Established Market Views 
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Estimation of the TNC Yield Curve 

● Estimation of the TNC yield curve at a point in time starts 

with Treasury nominal coupon issues in the market at that 

time (certain issues are eliminated, as described later).

● The regression terms are chosen to capture any hump and 

also to sort out the on-the-run and first off-the-run issues. 

● The par and spot rates are chosen to be those rates that 

give the best statistical fit (by least squares) to all the 

prices in the market. This means that the estimated prices 

of the issues, given as their cash flows discounted by the 

rates, come closest on average to their actual prices.
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Estimation of the TNC Yield Curve, continued 

● The TNC yield curve methodology employs a model of bond 

prices. The methodology does not directly use yields or 

averages of yields of the securities.

● However, the description so far of the estimation is too 

general to actually compute yield curves. To carry out the 

estimation, yields must be assumed to follow a 

mathematical pattern or functional form.

● The main source of differences among yield curve 

approaches is their different choices of functional forms, 

and as noted, functional forms in other approaches 

typically are not grounded in market hypotheses. The TNC 

methodology bases the functional form on hypotheses 

about maturity ranges in the market.
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The Forward Rate 

● The concept of the forward rate is useful for picking a 

functional form for estimating the yield curve.

● The forward rate is straightforward: for each maturity, 

consider entering into a contract to invest some money at 

the time of that maturity for a small amount of time 

beyond that maturity. The forward rate at that maturity is 

the future interest rate on this investment.
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The Forward Rate, continued 

● Analogous to spot rates, the market in general does not 

provide explicit forward rates, and they must be inferred 

from other yields in the market.

● The forward rate is higher at a given maturity when 

investors who are trading at that maturity are less eager to 

lend based on their assessment of uncertainty and their 

expectations and purposes, while borrowers are more 

eager to borrow based on their perceptions. The forward 

rate summarizes market views for each maturity in a 

single number.
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Maturity Ranges 

● Moreover, trading in securities tends to divide into 

maturity ranges, such that the trading activity in each 

range on average reflects similar purposes, similar views of 

risk, and similar expectations about securities in that 

range.

● Because market views can be considered similar for 

securities in the same range, the forward rates in each 

maturity range can be assumed to be related to each other 

in a simple fashion.

● Consequently, the TNC methodology models the forward 

rates in each maturity range as a smooth (cubic) function, 

and joins the functions together smoothly across ranges (as 

a cubic spline).
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Maturity Ranges, continued 

● The TNC methodology at the present time uses five 

maturity ranges, delineated by the maturity points 0, 1.5, 

3, 7, 15, and 30 years maturity. These points provide 

separate ranges for the critical maturities of 2 years, 5 

years, the benchmark 10 years, and 30 years.

● The choice of fixed maturity ranges increases significantly 

the stability of the TNC yield curve estimates over time.

● In addition, the TNC methodology is statistically 

straightforward to estimate. In contrast, certain other 

yield curve approaches generate statistical models that are 

ill-conditioned and unstable.
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The Long-Term Forward Rate 

● The methodology must include the capability of projecting 

forward rates beyond 30 years maturity so as to obtain 

yields out through 100 years maturity.

● First of all, the long-term forward rate beyond 30 years 

maturity is set to a constant, because there are not enough 

data to estimate accurately movements in the forward rate 

beyond 30 years maturity.
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The Long-Term Forward Rate, continued 

● Next, the TNC methodology postulates that the long-term 

forward rate is determined by the same factors that affect 

forward rates in the longest 15- to 30-year maturity range, 

since that range is sufficiently distant in time to reveal 

underlying long-term attitudes toward risk and return.

● Therefore, the constant long-term forward rate from 30 

years maturity up through 100 years maturity is taken to 

be the average forward rate in the 15- to 30-year maturity 

range.
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Estimation 

● The forward rates in the maturity ranges are estimated by 

least squares, and the par and spot yields are derived from 

the estimated forward rate curve.

● The regression terms are simultaneously estimated. 

Before estimation, the Treasury security data are weighted 

by the (square root of the) inverse of duration.
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Data 

● The TNC yield curve represents all nominal coupon issues, 

and the dataset for each business day is derived from 

issues that are priced on that day. Bid prices are used.

● However, the dataset for each day excludes issues with 

fewer than two coupon payments remaining.

● Also, the TNC curve here presented from 2003 forward 

excludes the 14 callable issues that were outstanding at 

some time during this period. The last callable issue was 

called in 2009, callables are no longer issued, and the 

callables do not affect results enough to add in the 

machinery to deal with call options.
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Results 

● The following charts show results for the TNC yield curve 

over the period January 2003 through March 2014, for a 

total of 2,080 business days and 135 months.

● The first chart in slide 26 shows monthly off-the-run par 

yields at 2 years, 5 years, 10 years, and 30 years 

maturities. The second chart in slide 27 shows the 

monthly off-the-run par yield curve over the entire period.

● The charts show that the par yield curve flattened out 

before the 2007-2009 recession, and that yield spreads 

were large in the financial crisis of 2009 forward. After 

that, spreads decreased a bit.
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2 Years

5 Years

10 Years

30 Years

TNC PAR YIELDS AT SELECTED MATURITIES

Monthly, Percent
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TNC PAR YIELD CURVE

Monthly, Percent

200320052007

2009

2011

20132014

2012
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Results, continued 

● The next chart in slide 29 shows the TNC quarterly 

average spot rates over the entire period at the maturities 

of 2 years, 5 years, 10 years, and 30 years, compared with 

the legacy Treasury spot rates from the Office of Thrift 

Supervision (OTS rates). And the chart after that in slide 

30 shows the 10-year average of the TNC quarterly spot 

yield curve from 2003QII through 2013QI compared with 

the 10-year average of the OTS legacy spot yield curve.

● The charts indicate that TNC spot rates are generally 

above OTS rates. In the last chart, the average difference 

between the two curves is 14 basis points through 30 years 

maturity.
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5 Years

10 Years

30 Years

TNC AND OTS SPOT RATES

AT SELECTED MATURITIES

Quarterly, Percent

TNC Rates in Color

OTS Rates in Black
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TNC AND OTS SPOT YIELD CURVES

10-Year Average Through March 2013, Percent

Maturity
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For More Information 

● The High Quality Market (HQM) Corporate Bond Yield Curve for 

the Pension Protection Act (PPA) is published by the IRS each 

month. Data are also available on the Economic Policy website. 

● For more details on the mathematics behind the HQM and TNC 

curves, and for more documentation in general, visit the Office of 

Economic Policy website. Go to www.treasury.gov, under 

“Resource Center” choose “Economic Policy,” then choose 

“Corporate Bond Yield Curve Papers.”

● The methodology here presented has been applied to Treasury 

inflation-indexed securities (TIPS). See papers 0601 and 0501 in 

the Economic Policy Research Paper Series on the Office of 

Economic Policy website.