For example, stock index futures, I have 65.438 billion in my hand, and the current futures index is 2000 points. Suppose 300 yuan has a margin of 10% for each point. At this time, I need a margin of 2000 * 300 * 1 0% = 60,000 yuan, and the remaining funds are 40,000 yuan. Suppose the stock index falls by 100 points, and I lose 300 *100 = 30,000 yuan. If we want to figure out how many points the index has to fall before it will break, let the limit falling position be x, and the equation can be listed as: X * 300 * 10% = 65438+ million -(2000-x)*300? (Note that the x here is not the number of dropped points, but the number of dropped points).
There is also a calculation based on funds. Divide the total funds in the account, that is, equity C, into two parts (the handling fee is ignored):
Answer? Margin b required for the transaction Available funds (A+B=C)
From the beginning to the end of the transaction, this equation must be maintained: A= contract value * margin rate.
It means: a participates in the transaction, is bound and cannot be moved; B is discretionary funds. If you think of A as a pool, you must keep the pool full during holding. If there is floating surplus, there is too much water, and pool A can't hold it, so it will automatically flow to B; On the other hand, floating loss and insufficient water must be replenished from B to A to maintain the full pool.
Initial C= 100000 yuan? After opening: A=2000*300* 10%=60000 yuan? Then B=C-A=40000 yuan. Holding period: when there is a loss of 30,000 yuan, that is, A is short of 30,000 yuan, a = 60,000-30,000 yuan, and a =1900 * 300 *10% = 57,000 yuan, at this time, 57,000-300,000 yuan is needed to hold positions. Then, the remaining B=40000-27000= 13000 yuan. C=A+B=57000+ 13000= 70000 yuan after a loss of 30000 yuan. 30000+70000= 100000)
Short position: if the loss continues to expand, because to maintain A, we must constantly transfer funds from B until B=0. There is no available funds, of course, it is an explosion!
Pay attention to a problem, that is, the margin rate. Under normal circumstances, the margin rate of futures companies will be increased by several percentage points on the basis of the exchange to control risks. If the margin rate is high, then the required A is also high, which will affect the reduction of B. Therefore, when to break the position depends on whether your contract with the futures company is based on the margin rate of the exchange or the margin rate of the futures company.