"Vertical arbitrage of call put options" is a call spread strategy using put options, which is used when the expected price of the subject matter rises.

Similar to the strategy of "vertical arbitrage of call options", investors buy put options with relatively low execution price. At the same time, when selling put options with relatively high strike price, the subject matter, maturity date and transaction quantity of the bought and sold options should be the same, thus establishing a combination of "vertical arbitrage of call put options". Because the higher the strike price of the put option, the more expensive the premium is, so the premium (P2) of the put option sold by investors is higher than that of the put option bought (P 1), and there will be a net cash inflow in the arbitrage portfolio, that is, the part where the premium collected exceeds the premium paid.

For example, an investor buys a 1 put option with an exercise price of 98, pays a premium of 1, and sells a 1 put option with an exercise price of 100, paying a premium of 2 (the subject matter and the expiration date are the same). Let's take a look at the profit and loss chart of this arbitrage portfolio. When the price exceeds 65,400 in the bull market, the investor will give up the put option premium in his hand, and his opponent will also give up the premium, so the investor will steadily get a premium of 2- 1= 1, which is the "vertical arbitrage of bull put options":