Basic principles of pricing

Term Structure and bond which matures in n years Credit Spread Estimation investor gets at the times i = 1,... n coupon payments C and a redemption payment R at t = n

pc is quoted on the market Management Science Lab in Finance, 2005 seller also receives accrued for holding the bond over the period since the last coupon payment M. Ablasser, J. Hayden, D. Kopp, C. Leitner, M. Schweitzer, R. Wittchen, A. Wurzer number of days since last coupon a = C number of days in current coupon period

investor has to pay the dirty price pd bond pricing equation with continuous compounding

n X −simi −snmn pc + a = C e + Re June 15, 2006 i=1

Term Structure and Credit Spread Estimation Robert Ferstl 1 / 9 Term Structure and Credit Spread Estimation Robert Ferstl 2 / 9 Basic principles of bond pricing Term structure estimation

yield to estimate zero-coupon yield curves and credit spread curves from n market data X −ymi −ymn pc + a = C e + Re usual way for calculation of credit spread curves i=1 ci(t) = si(t) − sref (t) equivalent formulation of the bond price equation uses the −simi parsimonious approach widely used by central banks discount factors di = δ(mi) = e

continuous discount function δ(·) is formed by interpolation of Yield curves Spread curves the discount factors n 0.038 X

pc + a = C δ(mi) + δ(mn)R 0.036 0.0015 i=1 implied j-period forward rate 0.034 0.0010 0.032

js − ts Yields j t Spreads ft|j = 0.0005

j − t 0.030 duration is a weighted average of time to cash flows 0.028 0.0000 " n # GERMANY 1 AUSTRIA AUSTRIA

X 0.026 ITALY ITALY D = C δ(mi)mi + δ(mn)Rmn pc + a 5 10 15 −0.0005 5 10 15 i=1 Maturities Maturities

Term Structure and Credit Spread Estimation Robert Ferstl 3 / 9 Term Structure and Credit Spread Estimation Robert Ferstl 4 / 9 Nelson and Siegel (1987) approach Nelson and Siegel (1987) approach

Instantaneous forward rates m m m f (m, b) = β0 + β1 exp(− ) + β2 exp(− ) τ1 τ1 τ1 Spot rates

m m ! 1.0 1 − exp(− ) 1 − exp(− ) τ1 τ1 m s(m, b) = β0 + β1 m + β2 m − exp(− ) τ1 τ1 τ1 0.8 β1(m τ1) β2(m τ1)exp(− m τ1) β 0 Objective function 0.6 n X 2 bopt = min ωi Pˆi − Pi weighted price errors Model curves 0.4 b i=1 n

0.2 X 2 bopt = min (ˆyi − yi) yield errors b i=1 0.0

0 2 4 6 8 10

Time to maturity

Term Structure and Credit Spread Estimation Robert Ferstl 5 / 9 Term Structure and Credit Spread Estimation Robert Ferstl 6 / 9 Extensions References I

Svensson (1994) extended the functional form by two additional Bank for International Settlements parameters which allows for a second hump-shape Zero-coupon yield curves: technical documentation Instantaneous forward rates BIS Papers, No. 25, October 2005 m m m m m David Bolder, David Streliski f (m, b) = β0 + β1 exp(− ) + β2 exp(− ) + β3 exp(− ) τ1 τ1 τ1 τ2 τ2 Modelling at the Bank of Canada Bank of Canada, Technical Report, No. 84, 1999 simple calculation method of credit spread curves could lead to twisting curves Alois Geyer, Richard Mader Estimation of the Term Structure of Interest Rates - A Parametric Jankowitsch and Pichler (2004) proposed a joint estimation Approach method, which leads to smoother and more realistic credit spread OeNB, Working Paper, No. 37, 1999 curves

Term Structure and Credit Spread Estimation Robert Ferstl 7 / 9 Term Structure and Credit Spread Estimation Robert Ferstl 8 / 9 References II

Rainer Jankowitsch, Stefan Pichler Parsimonious Estimation of Credit Spreads The Journal of , 14(3):49–63, 2004 Charles R. Nelson, Andrew F. Siegel Parsimonious Modeling of Yield Curves The Journal of Business, 60(4):473–489, 1987 Lars E.O. Svensson Estimating and Interpreting Forward Interest Rates: Sweden 1992 -1994 National Bureau of Economic Research, Technical Report, No. 4871, 1994

Term Structure and Credit Spread Estimation Robert Ferstl 9 / 9