一种投资策略，预期某种证券价格将上涨，但为了避免因预测错误、证券价格下跌会造成损失而采取的操作策略。

An bullish strategy used by investors who feel that the market price of a commodity will appreciate but wish to limit the downside potential associated with an incorrect prediction.

A bull vertical spread requires the simultaneous purchase and sale of options with different strike prices, but of the same class and expiration date.