追加保证金怎么算

追加保证金是在金融交易，特别是期货和期权交易中一个重要的概念。它对于投资者和交易机构都具有关键的意义。

首先，我们来了解一下什么是追加保证金。追加保证金是指投资者日终时仍有未平仓合约时需缴纳的保证金。在期权交易中，保证金的缴纳方式可以选择现金或者股票等其他形式。简单来说，期权保证金的作用是防止投资者在期权交易中，亏损超过他们已经支付的保证金金额。如果投资者不能履行其期权合约的义务，那么将失去其支付的保证金。但如果投资者能够在期权交易中成功履行其义务，将会获得其支付的保证金和所有盈利。

接下来，我们通过具体的例子来看看追加保证金是如何计算的。

例 1：某客户账户原有保证金 500000 元，某日上午，在指数 2200 点开仓买进 5 手当月沪深 300 股指期货合约，午后指数一路下跌，该交易者没有平仓。当日结算价为 2150 点，假定交易保证金比例为 15%，手续费为单边每手 0.3，则客户的账户情况为：开仓买进 5 手时需要保证金=2200×300×5×15%=495000 元。可见，开仓时资金还是足够的，但由于指数当日下跌，结算价为 2150 点，该交易者：当日开仓持仓盈亏=(2150 - 2200)×300×5 = -75000 元；扣除当日亏损及手续费后实际当日权益=500000 - 75000 - 99 = 424901 元；而 5 手合约持仓需要保证金=2150×300×5×15% = 483750 元；资金余额(即可交易资金)=424901 - 483750 = -58849 元。权益小于保证金，导致资金余额为负数。显然，要维持 5 手的多头持仓，保证金尚缺 58849 元，意味着下一交易日开市之前必须追加保证金 58849 元。如果该客户在下一交易日开市之前没有将保证金补足，那么期货公司可以对其持仓实施部分强制平仓。经过计算，424901 元的权益可以保留的持仓至多为 424901/2150×300×15% = 4.39 手。因此，期货公司至少可以将其持仓强平掉 1 手。

例 2：某客户帐户原有保证金 200,000 元，8 月 9 日，开仓买进 9 月沪深 300 指数期货合约 15 手，均价 1200 点(每点 100 元)，手续费为单边每手 10 元，当日结算价为 1195 点，保证金比例为 8%。当日开仓持仓盈亏=(1195 - 1200)×15×100 = -7,500 元，手续费=10×15 = 150 元，当日权益=200,000 - 7500 - 150 = 192,350 元，保证金占用=1195×15×100×8% = 143,400 元，资金余额(即可交易资金)=192,350 - 143,400 = 48,950 元。8 月 10 日，该客户没有交易，但 9 月沪深 300 指数期货合约的当日结算价降为 1150 点，当日帐户情况为：历史持仓盈亏=(1150 - 1195)×15×100 = -67,500 元，当日权益=192,350 - 67,500 = 124,850 元，保证金占用=1150×15×100×8% = 138,000 元，资金余额(即可开仓交易资金)=124,850 - 138,000 = -13,150 元。显然，要维持 15 手的多头持仓，保证金尚缺 13,150 元，这意味着下一交易日开市之前必须追加保证金 13,150 元。如果该客户在下一交易日开市之前没有将保证金补足，那么期货经纪公司可以对其持仓实施部分强制平仓。经过计算，124,850 元的权益可以保留的持仓至多为 124,850 元/(1150×100×8%) = 13.57 手。

例 3：假设你的保证金恰好为满足 3000 点时所需保证金金额，也就是 108000 元。这时，账户实际保证金余额为 108000 - 120000 = -12000 元。而这时，所需保证金为 2600×300×0.12 = 93600，才能满足保留一手 2600 点时的。跌倒 2600 之后，多一手股指会损失(3000 - 2600)×300 = 120000。而这时，所需保证金为 2600×300×0.12 = 93600，才能满足保留一手 2600 点时的多单。所以，共需补足保证金为 -12000 - 93600 = 105600。

综上所述，追加保证金的计算需要考虑多个因素，包括初始保证金、持仓盈亏、手续费、结算价等。投资者在进行金融交易时，务必充分了解相关规则和风险，以避免因保证金不足而导致的强制平仓等风险。

How to Calculate Margin Calls

Margin calls are a crucial concept in financial trading, especially in futures and options trading. They are of significant importance to both investors and trading institutions.

Firstly, let's understand what a margin call is. A margin call refers to the additional margin that an investor is required to deposit when they have open positions at the end of the trading day. In options trading, the margin can be paid in forms such as cash or stocks. Simply put, the role of the option margin is to prevent investors from losing more than the margin they have already paid in the options trading. If an investor fails to fulfill their option contract obligations, they will lose the margin they have paid. However, if they successfully fulfill their obligations in the options trading, they will receive their paid margin and all profits.

Next, let's take a look at how margin calls are calculated through specific examples.

Example 1: A client's account originally had a margin of 500,000 yuan. On a certain morning, they opened a position to buy 5 lots of the current month's CSI 300 stock index futures contract at an index of 2200. The index dropped throughout the afternoon, and the trader did not close the position. The settlement price for the day was 2150. Assuming the trading margin ratio was 15% and the handling fee was 0.3 per lot for one side, the account situation of the client was as follows: The margin required to open the position for 5 lots was 2200×300×5×15% = 495,000 yuan. It can be seen that the funds were sufficient at the time of opening the position. However, due to the drop in the index on the same day and the settlement price of 2150, the trader: The profit and loss of the open position for the day was (2150 - 2200)×300×5 = -75,000 yuan; The actual equity after deducting the loss and handling fee for the day was 500,000 - 75,000 - 99 = 424,901 yuan; The margin required for the 5-lot position was 2150×300×5×15% = 483,750 yuan; The available trading funds (i.e., the fund balance) was 424,901 - 483,750 = -58,849 yuan. The equity was less than the margin, resulting in a negative fund balance. Obviously, to maintain the 5-lot long position, the margin was still short by 58,849 yuan, meaning that a margin call of 58,849 yuan must be met before the