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Capital Budget<strong>in</strong>g <strong>in</strong> Banks 253<br />

The model presented above shows how RAROC has to be constructed<br />

so that it can be <strong>com</strong>pared to the cost of equity capital as determ<strong>in</strong>ed for<br />

example, by the CAPM. RAROC therefore assumes that economic capital<br />

is <strong>com</strong>pensated by the market <strong>and</strong> that it is the correct risk measure. Only<br />

then are decisions based on RAROC versus R E<br />

h<br />

consistent with maximiz<strong>in</strong>g<br />

value. However, this assumes that the risk<strong>in</strong>ess of the economic capital is the<br />

same as that of the bank’s equity capital 64 <strong>and</strong> that hence economic capital<br />

has to earn the same returns as the equity capital.<br />

Given the discussion <strong>in</strong> the previous chapter <strong>and</strong> that economic capital<br />

is assumed to be <strong>in</strong>vested <strong>in</strong> a reserve pool to guarantee a certa<strong>in</strong> default<br />

probability, this seems unlikely to be the case. Additionally, <strong>and</strong> as po<strong>in</strong>ted<br />

out for <strong>in</strong>stance by Johann<strong>in</strong>g, economic capital determ<strong>in</strong>ed on a VaR basis<br />

is <strong>in</strong><strong>com</strong>patible with the maximization of expected utility <strong>in</strong> the neoclassical<br />

world. Therefore, RAROC is not a suitable <strong>in</strong>ternal performance measure<br />

<strong>in</strong> all circumstances. 65<br />

Deficiencies of RAROC<br />

In this section, we will discuss the deficiencies <strong>and</strong> fundamental problems of<br />

RAROC.<br />

Deficiencies of the Generic RAROC Model One of the advantages of RAROC mentioned<br />

previously, is that it adjusts the risk of any transaction to that of the<br />

bank’s equity by chang<strong>in</strong>g the leverage of the transaction via a different<br />

economic capital requirement. Therefore, RAROC avoids the need to estimate<br />

the external beta of the transaction. 66 There are two problems associated<br />

with this approach.<br />

First, the allocated capital is a cushion to absorb losses up to a prespecified<br />

confidence level <strong>and</strong>, therefore, a total risk measure. 67 The risk contributions<br />

of s<strong>in</strong>gle transactions are based on <strong>in</strong>ternal betas that are calculated<br />

vis-à-vis the exist<strong>in</strong>g bank portfolio. S<strong>in</strong>ce these results are <strong>com</strong>pared to<br />

externally driven hurdle rates, one has to assume that the bank portfolio is<br />

a good proxy for the market portfolio. 68 This might actually be correct,<br />

because typically we f<strong>in</strong>d bank betas to be around 1.0, 69 <strong>in</strong> which case one<br />

could show that the <strong>in</strong>ternal betas are similar (if not identical) to external<br />

64 See Crouhy et al. (1999), p. 6.<br />

65 See Johann<strong>in</strong>g (1998), pp. 73–86. We will address this problem below.<br />

66 See Crouhy et al. (1999), p. 7.<br />

67 See Grübel et al. (1995), p. 618.<br />

68 As claimed by Zaik et al. (1996), p. 87.<br />

69 See Schmittmann et al. (1996), p. 648, for large German universal banks (not niche<br />

players).

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