Box spread
ボックス・スプレッド。ブル・コール・スプレッドとベア・プット・スプレッドを組み合わせた4枚構成で固定価値を確定させる建玉。主に現金に近い資金調達取引として使われる。
A box spread combines a bull call spread and a bear put spread on the same underlying, using the same two strikes and expiration. Because the four legs together lock in a fixed payoff no matter where the stock ends up, the position behaves almost like a bond: you know today exactly what it will be worth at expiration. That known value is simply the difference between the two strikes.
Traders mainly use boxes to borrow or lend cash inside a margin account. Selling a box brings in premium now and obligates you to pay the strike width later, which is effectively taking out a short-term loan at an implied interest rate. Buying a box does the opposite, parking cash for a small guaranteed return. Say the strikes are 100 and 110: the box is worth 10 at expiration, so if you can buy it for 9.60 you earn the 0.40 spread.
The classic mistake is treating a box as risk-free. On American-style options early assignment can break the structure, and commissions plus the bid-ask on four legs often eat the tiny edge. Only European-style index options with tight spreads make boxes genuinely clean, which is why retail traders rarely find them worthwhile.
すべてのオプション用語
教育目的のみ。気配値は約15分遅延しており、本サイトの内容は投資助言ではありません。オプション取引には多大な損失リスクが伴います。