HKSI notes中有一個關於 Futures例子

You should know the concept of hedging --> risk management is the main purpose in this future transaction. In financial budgeting, we want to make sure everythihg is under control and cash flows follow our plans. We want to avoid unexpected losses or gains.

(1)
Say it is 1st Jan now, Anne has to borrow some money ($x) on 1st Apr. Since she does't know whether the interest rate will rise or drop in this 3 months, she wants lock the cost of borrowing (interest rate after 3 months) on 1st Jan. So she sells a future contract stating that she will provide a fixed interest rate for $x from 1st Apr to some time in futre.

(2)
Suppose the interest rate increases, Anne has to pay a higher interest when she borrows on 1st Apr, but the extra cost is offset by the profit from the future contract. So the net effect is the overall interest payout is still the same.

You may say that Anne will suffer a loss from the future contract if the interest rate drops. In fact the cost of her borrowing is reduced, and this reduced amount can be used to compensate the future loss. So the overall cost is exactly the same as what she planned in Jan.

Remember the future contract is used to lock the interest cost, instead of making profit(like what we do in equity market).

我考過呢個試，憑我僅餘記憶解釋，你睇下明唔明：

1. 首先你要明白, 買期貨並唔係真金白銀拎100%的錢出黎, 期貨有個特色係槓桿
好似呢個例子, 要對沖100萬元借貸的利息開支, 佢無須訂一份真金白銀俾100萬元的合約, 可能用10萬8萬已經做倒對沖

2. 呢度講o既應該係利率期貨

3. 假設俾10萬元買利率期貨, 去估將來利息會升
如果息升, 期貨會賺, 但你真正借果筆錢因為俾多左息, 因此會蝕
相反, 如果息跌, 期貨會蝕, 但借果筆錢付息少左, 結果又係打和
所以說, "the effective borrowing cost remains unchanged"

4. 而在買入期貨後, 三個月要賣出期貨, 原因係要平倉( "to offset the first contract")
呢張沽出的期貨合約, 唔洗再等三個月後處理
試想像, 你三個月前買左個手袋, 到三個月後的今天, 你將個手袋賣返出去黎「平倉」
你無多到個手袋, 手袋賣貴左你就賺, 賣平左你就蝕, 平倉已經係埋單計數!!

5. 結果係, 透過對沖, 你可以鎖定利息成本
惟一你「蝕左」o既係, 你要俾錢出黎買期貨, 即係果10萬8萬元
不過, 對於當事人黎講, 唔對沖要多付的利息成本, 分分鐘多過呢10萬8萬
所以雖然要俾多少少錢, 但佢地都會冒險, 會選擇用期貨做對沖