先定边界，再谈买卖。能力圈管住无知；市场先生提供价格，不提供真理。
英文为原文摘录；中文标「译文」。点击年份打开本站 letters/ 中的官方文件。
“What an investor needs is the ability to correctly evaluate selected businesses. Note that word "selected": You don't have to be an expert on every company, or even many. You only have to be able to evaluate companies within your circle of competence. The size of that circle is not very important; knowing its boundaries, however, is vital.”译文 投资者需要的，是正确评估「选定」企业的能力。你不必成为每家公司的专家——只要能评估能力圈内的公司。圈子大小并不重要；知道边界在哪里，才至关重要。
“In the short run, the market is a voting machine but in the long run it is a weighing machine.”译文 短期看，市场是投票机；长期看，市场是称重机。
flowchart LR
A[机会] --> B{在能力圈?}
B -->|否| C[走开]
B -->|是| D[评估生意]
D --> E{市场先生报价}
E -->|远低于价值| F[考虑买]
E -->|否则| G[等待]
示意图是阅读辅助，不是巴菲特原图。