1.Determine the standard deviation of portfolio returns:
according to the formula:
0.4, 0.6 - weight in securities portfolio
0.07, 0.1 -
standard deviation
"\\sigma=(0.4^2\\times0.07+0.6^2\\times0.1+2\\times0.4\\times0.6\\times0.07\\times0.1\\times0.1)^{1\/2}=(0.0112+0.036+0.000336)^{1\/2}=0.047536^{1\/2}=0.2180"
A confidence level of 99% corresponds to 2.33 standard deviations.
According to the formula, we determine the portfolio VaR:
Portfolio VaR for a given 'confidence level is determined by the following formula:
where VaRP - VaR portfolio;
PP - the value of the portfolio;
sigma p - standard deviation of portfolio returns corresponding to the time for which VaR is calculated;
z a - the number of standard deviations corresponding to the level
confidence probability.
"Var=Pp\\times\\sigma p\\times za"
"Var=100\\times0.2180\\times2.33=50.80"
2.
Calculate expected annual loss
"ECL=E(b)\u00d7E(CE)\u00d7E(LDG)"
Eb - probability of default
E(CE) - expected credit exposure
E(LDG) - expected severity
"0.06\\times100\\times 0.6 = 3.6"
unexpeted loss:
The loss distribution is a random variable with two states: default (loss of $60M, after recovery), and no default (loss of 0). The expectation is $3.6M. According to the variance formula of the random value
"0.06 \\times(60-3.6)^2 + 0.94 \\times (0-3.6)^2 =203.04"
The unexpected loss is therefore
Standard deviation:
"\\sqrt{203.04} = 14.25"
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