CHAPTER 33 Mathetnatical Considerations for Index Products In this chapter, we look at some riskless arbitrage techniques as they apply to index options. Then a summary of mathematical techniques, especially modeling, is pre­ sented. ARBITRAGE Most of the normal arbitrage strategies have been described previously. We will review them here, concentrating on specific techniques not described in previous chapters on hedging (market baskets) and index spreading. DISCOUNTING We saw that discounting in cash-based options is done with in-the-money options as it is with stock options. However, since the discounter cannot exactly hedge the cash­ based options, he will normally do his discounting near the close of the day so that there is as little time as possible between the time the option is bought and the close of the market. This reduces the risk that the underlying index can move too far before the close of trading. Example: OEX is trading at 673.53 7nd an arbitrageur can buy the June 690 puts for 16. That is a discount of 0.47 since,parity is 16.47. Is this enough of a discount? That is, can the discounter buy this put, hold it unhedged until the close of trading, and 641