外匯的保證金、保證金水平與強制平倉是什麼？
保證金是槓桿交易未平倉期間，經紀商把您的資金鎖住、當作押金的部分。保證金水平等於淨值除以已用保證金，再乘以 100%。當它跌到經紀商的追繳保證金水平時，您的帳戶會被標記警示；跌到強制平倉水平時，經紀商就會開始自動平掉您的部位。
保證金是槓桿與您真實帳戶交會的地方。弄懂 MetaTrader 交易終端底部那幾個數字，您就能隨時知道自己距離被強制平倉還有多遠。
保證金是押金，不是費用
開立槓桿交易時，經紀商會把您的一部分資金預留為保證金。這筆錢並沒有被花掉。交易平倉後，它會還給您，再加上或減去這筆交易的損益。
所需保證金取決於部位大小與您的槓桿：
所需保證金 = 部位價值 ÷ 槓桿
以好算的示意價格舉例：一個 1:100 的 $1,000 帳戶，以 1.10000 買進 0.50 手 EUR/USD。部位價值是 $55,000，所以保證金是 $55,000 ÷ 100 = $550。
餘額、淨值與可用保證金
交易終端會顯示好幾個聽起來很像、意思卻不同的數字：
- 餘額（Balance）是來自已平倉交易、入金與出金的資金。它不計入未平倉的交易。
- 淨值（Equity）是餘額加上未平倉交易的浮動損益：也就是帳戶此刻的價值。
- 保證金（Margin）是未平倉部位佔用的金額，也稱為已用保證金。
- 可用保證金（Free Margin）是淨值減去保證金。它用來開新交易，也用來承受未平倉交易的虧損。
在開立上面那筆交易後、價格還沒變動之前，餘額與淨值都是 $1,000。保證金是 $550，所以可用保證金是 $1,000 減 $550 = $450。
保證金水平是什麼？
保證金水平告訴您，未平倉的交易有多少資金在支撐。MetaTrader 以百分比顯示：
保證金水平 = 淨值 ÷ 保證金 × 100%
在這個例子中，$1,000 ÷ $550 × 100% = 181.8%。數字越高，您的空間就越大。沒有任何未平倉交易時，就不會顯示保證金水平。
追繳保證金與強制平倉
經紀商會在保證金水平上設定兩個門檻。每家經紀商與每種帳戶類型的數字都不同，會列在帳戶條款中。本課只以 100% 與 50% 作為例子。
- 追繳保證金（Margin Call）是警示水平。帳戶會被標記，經紀商可能會聯絡您。在 100% 時，可用保證金已降到零，再也沒有餘力開新交易。
- 強制平倉（Stop Out）是經紀商系統出手的水平。掛單會被刪除，未平倉部位會被平倉，通常從虧損最大的那一筆開始，直到保證金水平回升為止。
現在跟著這個例子，看看 EUR/USD 下跌時會發生什麼事。0.50 手的部位每點虧損 $5。為了讓計算簡單，保證金固定在 $550；在真實平台上，它會隨歐元價格變動而略有改變。
| EUR/USD | 反向點數 | 浮動虧損 | 淨值 | 保證金水平 |
|---|---|---|---|---|
| 1.10000 | 0 | $0 | $1,000 | 181.8% |
| 1.09500 | 50 | $250 | $750 | 136.4% |
| 1.09100 | 90 | $450 | $550 | 100%（追繳保證金） |
| 1.08550 | 145 | $725 | $275 | 50%（強制平倉） |
下跌 145 點，大約 1.3%，就足以讓這筆交易被平倉。交易者虧損 $725，剩下 $275。
價格能變動多少才會觸發強制平倉？
您可以在交易之前就算出來，只要用上部位的每點價值：
距離強制平倉的點數 =（淨值減去強制平倉水平 × 保證金）÷ 每點價值
以這個例子計算：($1,000 減去 50% × $550) ÷ $5 = $725 ÷ $5 = 145 點。和表格的結果一致。
改用 0.10 手再算一次。保證金是 $110，每點價值 $1，所以 ($1,000 減去 $55) ÷ $1 = 945 點。較小的部位能換來大得多的緩衝空間。
這也是為什麼單純的高槓桿本身並不危險。在 1:500 下，這筆 0.50 手的交易只會佔用 $110，強制平倉的距離會是 189 點，而不是 145 點。
真正的危險，是因為保證金看起來很便宜，就開出更大的部位。
如何與強制平倉保持安全距離
- 依照停損決定每筆交易的規模，就像手數課程所說的，讓一次正常的停損只花掉帳戶的一小部分。
- 除了獲利，也要留意保證金水平。多筆未平倉交易的保證金會相加。
- 預期換日與新聞前後點差會擴大。點差擴大會同時壓低每一筆未平倉交易的淨值。
- 在需要之前，先查清楚您經紀商的追繳保證金與強制平倉水平。
- 避免在虧損的交易上加碼攤平。這會在淨值下降的同時佔用更多保證金。
保證金計算機會在您下單前，顯示任何貨幣對、交易量與槓桿下這筆交易會佔用多少保證金。
常見問題
多少保證金水平才算好？
沒有官方標準。數字越高，您的交易就有越多空間；如果只略高於經紀商的追繳保證金水平，就幾乎沒有空間了。
觸發強制平倉時會發生什麼事？
經紀商的系統會刪除掛單，並以市價平掉未平倉部位，通常先從虧損最大的開始，直到保證金水平回到強制平倉水平之上。這筆虧損隨後就會反映在您的餘額中。
保證金是一種費用嗎？
不是。保證金是交易未平倉期間被鎖住、平倉後就會釋放的押金。交易的成本是點差、佣金與隔夜利息。
停損能防止強制平倉嗎？
通常可以，前提是停損設得合理，而且部位是依照停損來決定大小。在快速變動的市場或週末跳空時，價格可能同時跳過兩者，所以停損是一個計畫，而不是保證。
繼續學習
第 6 章What is margin trading?Margin trading means opening a position worth more than the money in your account. The broker sets aside part of your balance, the margin, as a deposit while the trade is open. Profit and loss are counted on the full position size, so small price moves change your balance much faster than the margin suggests.
第 6 章What is account balance in forex?Your account balance is the money in your trading account from deposits, withdrawals and closed trades, after booked costs such as commission and swap. It does not include open positions. While a trade is open the balance stays the same, and the floating profit or loss shows up in your equity instead.
第 6 章What is floating (unrealized) profit and loss?Floating profit and loss is the result your open trades would show if you closed them at the current price. It changes with every tick and moves your equity, while your balance stays the same. It becomes realized, and is added to or taken from your balance, only when the trade closes.
第 6 章What is used margin?Used margin is the total amount your broker sets aside to keep all your open positions open. Each position's margin is its notional value divided by your leverage, and used margin adds them up. It is not a fee: the money returns to free margin when you close the trades.
第 6 章What is equity in a trading account?Equity is your account balance plus or minus the floating profit or loss of your open trades. It shows what the account would be worth if you closed everything at current prices. With no trades open, equity equals balance. Brokers use it to work out free margin, margin level and stop outs.
第 6 章What is free margin?Free margin is the money in your trading account that is not locked up as margin for open trades. It equals equity minus used margin. You need free margin to open new positions, and it falls as open trades lose and rises as they gain. At zero, your margin level is 100%.
第 6 章What is margin level?Margin level is your equity divided by your used margin, multiplied by 100 and shown as a percentage. It tells you how much cushion your open trades have. At 100%, equity equals used margin and free margin is zero. Brokers set their margin call and stop out levels on this number, and the levels differ between brokers.
第 6 章What is a margin call?A margin call is your broker's warning that your margin level, equity divided by used margin, has fallen to a set threshold such as 100%. You usually cannot open new trades from that point. The call closes nothing by itself. If losses continue, the broker's stop out level is where positions start to be closed for you.
第 6 章What is a stop out level?The stop out level is the margin level at which your broker starts closing your open positions automatically, often beginning with the largest loss. If your stop out level is 50%, closing begins when equity falls to half your used margin. It is meant to stop your account sinking further, though a price gap can still push it below zero.
第 6 章Margin call example: margin call at 100% with no separate stop out.When a broker sets the margin call and the stop out both at 100%, the warning and the forced close happen at the same moment. In this example, a $1,000 account buys 0.50 lot of EUR/USD with $550 of margin at 1:100, and the trade is closed after a 90 pip fall, a $450 loss.
第 6 章Margin call and stop out example: 100% and 50%.In this example a $2,000 account buys 1 lot of EUR/USD at 1.10000 with $1,100 of used margin. The margin call at 100% arrives when equity falls to $1,100, 90 pips lower at 1.09100. The stop out at 50% closes the trade when equity reaches $550, at 1.08550, a loss of $1,450.
第 6 章What happens if you trade forex with $100?With $100 and 1:100 leverage, 0.01 lot of EUR/USD at 1.10000 uses $11 of margin and can move about 890 pips against you before a 100% margin call. At 0.05 lot the margin call comes after 90 pips, and 0.10 lot cannot be opened at all. Trade size decides how much room you have.
第 6 章Why margin call and stop out levels differ between brokers.Margin call and stop out levels are set by each broker, often per account type, within any rules from the regulator that licenses the account. In this lesson's example, one trade is closed after 90 pips at one broker and after 178 pips at another, so look up your own levels before you trade.
第 6 章外匯的槓桿是什麼？槓桿讓您能控制遠大於入金金額的部位。在 1:100 的槓桿下，每 $1 保證金可以持有 $100 的貨幣，所以 $110,000 的部位需要 $1,100。槓桿決定的是要佔用多少保證金，而不是每點值多少錢。您真正的風險，來自您選擇的部位大小。
第 6 章Margin cheat sheet.Balance is the cash from deposits, withdrawals and closed trades. Equity is balance plus the floating profit or loss on open trades. Used margin is the deposit your open trades hold, and free margin is equity minus used margin. Margin level is equity divided by used margin, times 100. A margin call warns; a stop out closes trades.
第 6 章How can you avoid a margin call?Margin level is your equity divided by your used margin, and a margin call comes when it falls to your broker's threshold. To stay clear, keep positions small compared with your equity, set stop losses that close losing trades long before that point, and leave plenty of free margin unused.
