5. Just as holders and writers of stock options bear the risk that transactions in the underlying security may be erroneously reported, holders and writers of index options bear the risk that the reported current index level may be in error. A person who buys or sells an index option at a premium based on an erroneously reported index level is bound by the trade and has no remedy under the rules of the options markets. Simi- lady. persons who exercise cash-settled index options or are assigned exercises based on erroneously re- ported index levels will ordinarily be required to make settlement based on the exercise settlement value as initially reported by the official source of the index, even if a corrected value is subsequently announced. References herein to index values "as initially re- ported" refer to the values initially reported by the source of the index as definitive, and not to any tenta- tive or preliminary values that may be announced at an earlier time subject to adjustment. In extraordinary circumstances (e.g., where an exercise settlement value as initially reported is obviously wrong and in- consistent with values previously reported, and a cor- rected value is promptly announced). OCC has discretion to direct that exercise settlements be based on a corrected exercise settlement value. Ordinarily, however, the exercise settlement value as initially re- ported by the official source of the Index will be conclu- sive for exercise settlement purposes. 6. A holder of a cash-settled index option who exer- cises it before the exercise settlement value of the in- dex for that day is available runs the risk that the level of the underlying index may subsequently change. If such a change causes the exercised option to fall out of the money, the exercising holder will be required to ay the difference between the exercise settlement value and the exercise price of the option (times the applicable multiplier) to the assigned writer.