To give you my opinion, the negative basis is the positive market, which is a simple question; Given the basis, you can directly compare it with the size. Whoever has a large absolute value will choose the one, because the basis will become smaller (you can understand that the spread will return to zero sooner or later, and only in this way will it be possible to hedge arbitrage); The only problem with this problem is the location fee. This is a cost item, which is deducted from the absolute value of the basis difference in September. After the ratio is greater than 70, determine the target selection and choose September; This piece should be selling the September contract. If it is arbitrage, you can buy the July contract.
In addition, this exam must not be rote. There are 12 kinds of positive and negative market binding basis. Unless you are sure that you have a superior memory, you must understand the principle. Pure original hand play, I hope it will help you, and I wish you a smooth exam ~
Attached is a case of 12 (it doesn't hurt to have a look if you are interested, and the profit depends on the sign multiplication of the first three items)
The relationship between the strength of basis and hedging profit and loss is shown in the following twelve situations:
Positive market (+), strong basis (-), buy hedge (+), loss (-);
Positive market (+), strong basis (-), selling hedge (-), profit (+);
Positive market (+), weak basis (+), hedging (+), profit (+);
Positive market (+), weak basis (+), selling hedge (-), loss (-);
The forward market becomes a reverse market (+), with a stronger basis (-), hedging buying (+) and loss (-);
The forward market becomes a reverse market (+), the basis is stronger (-), hedging is sold (-), and the profit is (+);
Reverse market (-), basis strength (+), buy hedge (+), loss (-);
Reverse market (-), basis (+), sell hedge (-), profit (+);
Against the market (-), weak base (-), buy hedge (+), profit (+);
Reverse market (-), basis weakening (-), selling hedging (-), loss (-);
The reverse market becomes a positive market (-), the basis weakens (-), hedging buys (+) and gains (+);
Reverse market becomes positive market (-), basis becomes weak (-), hedging sells (-), and losses (-).