Note 39  Fair values of financial assets and liabilities  continued  Significant unobservable inputs  The following table contains information about the significant unobservable inputs used in Level 3 valuations and the valuation  techniques used to measure fair value of instruments. The range of values represent the highest and lowest input used in the  valuation techniques. Therefore, the range does not reflect the level of uncertainty regarding a particular input, but rather the  different underlying characteristics of the relevant assets and liabilities.  Correlation is a measure of the relationship between the movements of two variables (i.e. how the change in one variable influences  a change in the other variable). Correlation is a key input of derivatives with more than one underlying and is generally used to value  hybrid and exotic instruments. Volatility is a measure of the variability or uncertainty in returns for a given derivative underlying. It represents an estimate of how  much a particular underlying instrument, parameter or index will change in value over time. Volatility is an input in the valuation of  derivatives containing optionality. Volatility and skew are impacted by the underlying risk, term and strike price of a derivative. Forward prices are a price or rate that is applicable to a financial transaction that will take place in the future. It is generally based  on the spot price or rate, adjusted for the cost of carry, and defines the price or rate that will be used to deliver a currency, bond,  commodity or some other underlying instrument in the future. A forward may also refer to the rate fixed for a future financial  obligation, such as the interest rate on a loan payment. Unlisted equity instruments are generally valued based on earning multiples of comparable companies. Significant unobservable  inputs may include earnings before interest, taxes, depreciation and amortisation (EBITDA) multiple, discount rate and forecast  earnings of the investee companies.  Inputs for unlisted equity securities  Forward prices  Volatility  Correlation  Range of inputs  Assets $m  Liabilities $m  Valuation  technique(s)  Significant unobservable  inputs  Minimum  value  Maximum  value  As at 31 Mar 2014  Equity and  equity linked  products  1,022  35  Discounted cash  flows  Discount rate  6.8%  25.0%  Pricing model  Volatility  9.2%  95.0%  Earnings multiple  0.4x  8.45x  Correlation  0.07  0.07  Market comparability  Price in %  (5.9)%  25.0%  Other products  1,163  84  Pricing model  Volatility  7.0%  93.5%  Correlation  -  1.00  Market comparability  Price in %  7.0%  214.0%  Total  2,185  119  203 