一种投资策略，预期某种证券价格将上涨，但为了避免因预期错误、证券价格下挫会产生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 appciate but wish to limit the downside potential associated with an incorrect pdiction.
A bull vertical spad requires the simultaneous purchase and sale of options with different strike prices, but of the same class and expiration date.