Options, futures and spot can be completely converted. For example, options can be synthesized into futures (buy bullish and sell bearish to synthesize long futures and buy bearish to synthesize short futures), and a theoretical futures price can be calculated according to the spot, so that they can be compared with each other. When the three futures prices are different, they can theoretically arbitrage each other. The arbitrage between options and spot is generally called conversion arbitrage and anti-conversion arbitrage, and the arbitrage between futures and spot is ours.

Spot is an option that can be delivered at any time, and can be withdrawn at any time like a demand deposit; Futures are basic contracts that can only be delivered on the agreed delivery date. Financial futures is also a kind of futures. Unlike commodity futures, financial futures are delivered in cash. The underlying contract of a commodity is a real commodity, and the underlying of financial futures is the underlying, such as stock index and national debt price.