Capital Market Instruments

This book is concerned with the valuation and analysis of capital market securities, and associated derivative instruments, which are not securities as such but are often labelled thus. The range of instruments is large and diverse, and it would be possible to stock a library full of books on various aspects of this subject. Space dictates that the discussion be restricted to basic, fundamental concepts as applied in practice across commercial and investment banks and financial institutions around the world. The importance of adequate, practical and accessible methods of analysis cannot be overstated, as this assists greatly in maintaining an efficient and orderly financial system. By employing sound analytics, market participants are able to determine the fair pricing of securities, and thereby whether opportunities for profit or excess return exist.

Chapter 4 introduced the concept of the yield curve. The analysis and valuation of debt market instruments revolves around the yield curve. Yield curve or term structure modelling has been extensively researched in the financial economics literature; it is possibly the most heavily covered subject in that field. It is not possible to deliver a comprehensive summary in just one chapter, but our aim is to cover the basic concepts. As ever, interested readers are directed to the bibliography, which lists the more accessible titles in this area.

In this chapter we consider some of the techniques used to actually fit the term structure. In theory we could use the bootstrapping approach described earlier. For a number of reasons, however, this does not produce accurate results, and so other methods are used instead. The term structure models described in the previous chapter defined the interest rate process under various assumptions about the nature of the stochastic process that drives these rates. However the zero-coupon curve derived by models such as those described by Vasicek (1977), Brennan and Schwartz (1979) and Cox, Ingersoll and Ross (1985) do not fit the observed market rates or spot rates implied by market yields, and generally market yield curves are found to contain more variable shapes than those derived using term structure models. Hence the interest rate models described in Chapter 7 are required to be calibrated to the market, and in practice they are calibrated to the market yield curve. This is carried out in two ways: either the model is calibrated to market instruments such as money market products and interest-rate swaps, which are used to construct the yield curve, or the yield curve is constructed from market instrument rates and the model is calibrated to this constructed curve. If the latter approach is preferred, there are a number of non-parametric methods that may be used. We consider these later.

For market practitioners, zero-coupon rate curves are the basic tools used to value interest-rate based instruments. Curves are built using market data such as money market rates, swap rates, interest rates futures or bond prices as inputs. Despite the name, it is not in fact the ‘zero coupon’ rates that are the most important output from a curve fitting methodology, but rather a set of quantities known as discount factors. It is these that are crucial for the pricing of interest rate-based instruments.

In certain countries there is a market in bonds whose return, both coupon and final redemption payment, is linked to the consumer prices index. Investors’ experience with inflation-indexed bonds differs across countries, as they were introduced at different times, and as a result the exact design of index-linked bonds varies across the different markets. This of course makes the comparison of issues such as yield difficult, and has in the past acted as a hindrance to arbitrageurs seeking to exploit real yield differentials. In this chapter we highlight the basic concepts behind the structure of indexed bonds and show how these differ from those employed in other markets. Not all index-linked bonds link both coupon and maturity payments to a specified index; in some markets only the coupon payment is index-linked. Generally the most liquid market available will be the government bond market in index-linked instruments.

In Chapter 11 we introduced asset-backed bonds, debt instruments created from a package of loan assets on which interest is payable, usually on a floating basis. The asset-backed market was developed in the United States and is a large, diverse market containing a wide variety of instruments. The characteristics of asset-backed securities (ABS) present additional features in their analysis, which are investigated in this and the next two chapters. Financial engineering techniques employed by investment banks today enable an entity to create a bond structure from any type of cash flow; the typical forms are high volume loans such as residential mortgages, car loans and credit card loans. The loans form assets on a bank or finance house balance sheet, which are packaged together and used as backing for an issue of bonds. The interest payments on the original loans form the cash flows used to service the new bond issue.

Swaps are off-balance sheet instruments involving combinations of two or more basic building blocks. Most swaps involve combinations of cash market securities, for example a fixed interest rate security combined with a floating interest rate security, possibly also combined with a currency transaction. The market has also seen swaps that involve a futures or forward component, as well as swaps that involve an option component. The main types of swap are interest rate swaps, asset swaps, basis swaps, fixed-rate currency swaps and currency coupon swaps.