Risk-free arbitrage is a kind of intertemporal arbitrage, which refers to an operation mode of how to grasp the main position and end the transaction through hedging or delivery when the price difference between contracts in different delivery months of the same commodity changes abnormally, and how to establish equal positions in the opposite direction in different contract months of the same futures commodity. Among them, the arbitrage involved in the actual warehouse receipt delivery is risk-free arbitrage, because it is based on strict position cost and position conditions and is generally not affected by market fluctuations. Of course, "risk-free" arbitrage opportunities with stable returns that meet such conditions are rare, and once they appear, they will often attract funds to actively participate.

There are mainly five kinds of risk-free arbitrage in the market, namely, the way to buy back stocks and the significance of stock repurchase, arbitrage opportunities in share reform, arbitrage opportunities in the impact of mergers and acquisitions on stock prices, privatization themes, and fund opening. ETF index funds and corresponding stocks may also have arbitrage opportunities in mutual fluctuations.

The risk-free arbitrage model can be summarized as follows: when the actual spread >; When arbitrage cost, intertemporal profit = actual spread-arbitrage cost. When the profit reaches a certain level, the profit is closed. When the price difference between the two contracts rises in the opposite direction, it can be delivered at maturity to obtain stable arbitrage profits and achieve the purpose of risk-free arbitrage. Of course, the opportunity of risk-free arbitrage can't appear often, but once it appears, it will be the most stable way to obtain income.