Calculation of short indices
The short indices of Wiener Börse AG are continuously calculated during trading hours without using an initial value or an initial capitalization. The new index value equals that of the previous day multiplied by the weighted price changes of the individual shares. Hereby, the inverse index value is calculated by subtracting the absolute development of the underlying index from 2. The second term represents additional interest gains on the proceeds from short selling of the underlying index. The afore mentioned proceeds will accrue interest in accordance with the relevant EONIA interest rate and this increases the index values of the short indices.
Please note, that dividends are considered for the calculation of a short index. For clearer
understanding, the formula below shows the calculation without dividend adjustments.
| Symbol | Description |
|---|---|
| Index t | Value of the index at time t (current trading day) |
| Index t-1 | Value of the index at time t-1 (last trading day) |
| EONIA | Value of the interbank rate EONIA at time t-1 |
| d | Number of days between the trading days |
| t | Current trading day |
| t-1 | Last trading day |