1. London 25 September 2008 Measuring the Risk Free Rate in the UK Regulatory Context Water UK Cost of Capital Seminar 2008 Dr Richard Hern Tomas Haug

2. 1 Overview 1.The Real Risk Free Rate (RFR) in the CAPM 2.Recent UK Regulatory Decisions on RFR 3.Why UK Index Linked Gilts no longer provide good evidence on RFR 4.Evidence on RFR from the UK SWAP market Key points 5.International Evidence on RFR

3. 2 Defining the Risk Free Rate in the CAPM Under the CAPM framework, the cost of equity can be broken into two components –the expected RFR –the expected risk premium (=expected beta * expected market risk premium) UK Regulators have traditionally estimated the expected RFR using historical data on Index Linked Gilts (ILGs) –most regulators have used long maturity bonds to reflect utility asset lives

4. 3 Recent UK Decisions Can No Longer be Justified Under ILG Evidence UK RFR decisions stabilised at 2.5% in recent years, despite a downward trend in ILG yields

5. 4 Latest Data on UK ILGs Show Numbers Significantly Below 2.5% Yields on long dated UK ILGs (> 10 years) are currently less than 1% and less than 2% over all historical time periods

6. 5 Comparing Measures of the RFR Across Markets Data sourced from US Treasury, Agence France Tresor, Bundesbank, Bank of England and Consensus Economics UK yields on 20Y ILGs trade currently below 0.7%. This compares to real yields of 1.8% in France, 2.1% in the US and 2.8% in Germany

7. 6 Actuarial Requirements Have Depressed UK Gilt Yields Below the True RFR First noted in 1999: –Actuarial & regulatory influences have ensured continued strong demand for ILGs keeping their yields below the likely true level of real interest rates in the wider economy. (Bank of England, August 1999) Impact even stronger in 2008: –… strong pension fund demand for inflation-protected bonds has pushed down their yields...this demand may reflect several regulatory and accounting changes [FRS17, IAS19] over the past few years that have encouraged pension funds to seek to match their liabilities more closely with inflation-linked assets Bank of England (2008 Q2) ILG yields versus UK Pension Fund ILG Balance Sheet Position Source: Bank of England and ONS

8. 7 Academics Have Proposed Using Swaps as an Alternative Measure of the RFR Choudhry (2005) states: –Government bond markets (…) have experienced low liquidity and supply constraints, leading to inverted curves, causing some commentators to suggest that the government yields have traded below the true risk-free level. –[The] government curve may on occasion be overvalued, whereas the swap curve can be regarded as lying at fair value. –[The] only plausible alternative to the government yield curve in the euro and sterling market appears to be the interest rate swap. –The swap market, however, is now very large and liquid, and does not suffer from illiquidity, even out to long-dated maturities. There are also no supply constraints in the swap market, unlike for (say) long-dated gilts or Treasuries. Feldhutter and Lando (2007) state: –…the riskless rate is better proxied by the swap rate than the Treasury rate for all maturities. Hull, Predescu, and White (2004) estimate a risk-free rate for the US market using swap rates and CDS premiums –The 5Y Treasury yield lies 60 bps below the true risk-free rate –The 5Y true risk-free rate is on average around 10 bps less than the swap rate

9. 8 Estimating the RFR from Swaps Requires Adjusting for Banking Sector Credit Risk 1.Adjusting for credit risk: –Floating leg of swap is tied to 6-month Libor –Hence, credit risk in swaps reflects credit risk in 6-month Libor Libor is set by 16 banks with AA rating (or better) Credit risk in Libor is refreshed periodically (as low credit banks drop from Libor panel) –We use default insurance for banks (CDS) to adjust for interbank credit risk 2.Converting nominal to real yields: –Swaps are nominal and need to be adjusted for inflation expectations –Oxford Economic Forecasting (OEF) provide medium-term RPI forecast Swap Rate = true RFR + Credit Risk

10. 9 CDS Best Available Market Data t o Estimate Credit Risk in Banking Sector We use data on default insurance, i.e. Credit Default Swaps (CDS) to estimate interbank credit risk We use iTraxx CDS index of 5Y Senior Financials issued in Jun-2004 –Index is highly standardised and rules ensure only most liquid entities are included –We believe best available market data to measure interbank credit risk Source: International Swap and Derivatives Association Note: (*) swap data included interest rate swaps, currency swaps and interest rate options Growth in CDS Market Worldwide Since 2003, CDS notional amount outstanding exceeded total equity derivatives outstanding Back in Nov-05, S&P stated: –The increasing liquidity of the CDS market (…) makes CDS good proxies for cash bonds.

11. 10 Evidence on UK Real RFR from Swaps Similar to Other Markets Real RFR across Markets and Instruments Swap-based RFR similar across markets in range of 2.1-2.6% Swap-based RFR in UK similar to gilt yields in other markets

12. 11 Swap-based RFR (real) versus 5Y ILGs

13. 12 CC and UK regulatory decision no longer justified using ILGs UK ILG evidence does not provide good measure for true Risk Free Rate Strong academic support for swaps as basis for RFR UK Swap-based RFR is ~2.5%, which is in line with CC & regulatory precedent similar to evidence on RFR from other developed markets Key Points