Opportunity Cost
Every “buy” decision is a rejection of another best alternative
📌 Concept Explanation
Opportunity Cost = The value of the best alternative foregone when you make a choice.
You have 100,000 yuan. You could deposit it in the bank for 3% interest, or buy a stock you’re optimistic about. If you buy the stock, your opportunity cost is that 3% risk-free interest. If the stock only rises 2% in a year, you’ve actually lost—not lost money, but lost opportunity. What Duan Yongping means by “reasonable price” essentially is: the return on this investment must be significantly higher than the best alternative you can find.
💡 Core Understanding
1. “Holding” equals “buying” at every point in time—opportunity cost is the core tool for deciding whether to continue holding.
This means you’re making a decision every day: continue holding, or switch to something better? If the company you hold isn’t the best choice available to you right now, you should switch.
2. Timing judgment for buying is essentially comparison of opportunity costs—“reasonable price” refers to relative to your own opportunity cost.
3. Opportunity cost is the sole basis for stock-switching decisions—the choice between two stocks is a comparison of opportunity costs.
4. The minimum benchmark for opportunity cost is the risk-free rate—an investment return must significantly exceed the risk-free rate to be worthwhile.
If an investment’s expected return can’t even beat the risk-free rate, there’s no point doing it. “My understanding should relate to long-term interest rates. My understanding of investment is comparing against risk-free interest.”
🛠 How to Practice
Whenever making buy/hold/sell decisions, ask yourself:
- Is what I’m currently holding the best choice available to me right now? If not, consider switching. “Holding equals buying at every point in time”—don’t lazily continue holding just because “I already own it.”
- Does this investment’s expected return significantly exceed the risk-free rate? If only slightly higher, considering risk and uncertainty, it may not be worth doing.
- Is the reason for switching stocks based on opportunity cost, or just because another one “looks better”? “Switching portfolios for the sake of switching will probably be wrong”—stock switching needs clear opportunity cost judgment, not gut feeling.
⚠️ Common Misconceptions
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❌ “As long as this stock can make money, it’s worth holding” — The standard for holding isn’t “can it make money” but “relative to other alternatives, is this the best choice?” “If you can confirm it’s 40 cents vs 90 cents, why not switch?” Opportunity cost thinking requires you to always compare, not sit on one stock motionless. (Source: Investment Logic Chapter, 2010-04-27)
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❌ “Switching stocks is too troublesome, better to just keep holding” — The basis for switching stocks is opportunity cost, not whether it’s troublesome. “This is an opportunity cost question only you can answer. Of course, switching portfolios for the sake of switching will probably be wrong.”—The meaning here is: if you can’t clearly confirm the new target is significantly better, don’t switch; but if you can confirm it, you should switch. (Source: Investment Logic Chapter, 2018-10-09)
💬 Original Quotes
“Opportunity Cost refers to the maximum benefit forgone after making a choice—the benefit that could have been gained by not making that choice. Any decision requires making certain choices; the highest-value option among those discarded is the opportunity cost of that decision.” — Duan Yongping (Source: Investment Logic Chapter, 2013-03-22)
“‘Reasonable price’ mainly refers to your own opportunity cost. If you just leave money in the bank earning 1%/year interest, 8% annual return is very good—don’t listen to stories about neighbor Xiao Ma making lots of money, even if those stories are true.” — Duan Yongping (Source: Investment Logic Chapter, 2019-05-17)
“‘Holding’ at each moment indeed equals ‘buying’—that’s what opportunity cost means!” — Duan Yongping (Source: Investment Logic Chapter)
“Think 10 years ahead, relative to your own opportunity cost.” — Duan Yongping (Source: Investment Logic Chapter, 2020-11-02)
🔗 Related Nodes
Upstream Concepts (prerequisites for understanding this concept): Intrinsic Value · Circle of Competence · Buy Logic
Downstream Concepts (conclusions derived from this): Sell Logic · Concentrated Investing · Margin of Safety
Related Figures Duan Yongping · Munger
机会成本
每一个”买”的决定，都是在放弃另一个最好的选择
📌 概念解析
机会成本 = 你做了一个选择，所放弃的其他最佳选项的价值。
你手里有10万块，可以存银行吃3%利息，也可以买一只你看好的股票。如果你买了股票，你的机会成本就是那3%的无风险利息。如果这只股票一年只涨了2%，你其实是亏了——不是亏了钱，而是亏了机会。段永平说的”价格合适”，本质上就是：这笔投资的回报，要明显高于你能找到的其他最好的选择。
💡 核心理解
1. “持有”在每个时点都等于”买入”——机会成本是判断是否继续持有的核心工具。
这意味着你每天都在做一个决定：继续持有，还是换成更好的标的？如果你持有的公司不是你当下能找到的最好选择，就应该换。
2. 买入时机的判断，本质是机会成本的比较——“价格合适”指的是相对于你自己的机会成本。
3. 机会成本是换股决策的唯一依据——两只股票之间的选择，就是机会成本的比较。
4. 机会成本的最低基准是无风险利率——投资回报必须明显高于无风险利率才值得做。
如果一笔投资的预期回报连无风险利率都跑不赢，就没有做的必要。“我的理解应该和长期利息相关。我对投资的理解就是比较无风险利息。”
🛠 如何实践
每次做买入/持有/卖出决策时，问自己：
- 我现在持有的，是我当下能找到的最好选择吗？ 如果不是，就应该考虑换。“持有在每个时点都等于买入”——不要因为”已经持有了”就惰性地继续持有。
- 这笔投资的预期回报，明显高于无风险利率吗？ 如果只是略高，考虑到风险和不确定性，可能不值得做。
- 换股的理由是机会成本，还是只是觉得另一只”看起来更好”？ “为调仓而调大概率会是错的”——换股需要有明确的机会成本判断，而不是凭感觉。
⚠️ 常见误区
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❌ “只要这只股票能赚钱，就值得持有” — 持有的标准不是”能不能赚钱”，而是”相对于其他选择，这是不是最好的选择”。“如果你能确认是4毛对9毛，那为什么不换？“机会成本思维要求你永远在比较，而不是守着一只股票不动。（来源：投资逻辑篇，2010-04-27）
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❌ “换股太麻烦，不如一直持有” — 换股的依据是机会成本，不是麻烦与否。“这是个机会成本问题，只有自己可以回答。当然，为调仓而调大概率会是错的。“——这里的意思是：如果你不能确认新标的明显更好，就不要换；但如果确认了，就应该换。（来源：投资逻辑篇，2018-10-09）
💬 原文金句
“机会成本（Opportunity Cost）是指做一个选择后所丧失的不做该选择而可能获得的最大利益。任何决策，必须作出一定的选择，被舍弃掉的选项中的最高价值者即是这次决策的机会成本。” — 段永平（来源：投资逻辑篇，2013-03-22）
“价格合适主要指的是你自己的机会成本。如果你只是把钱放在银行吃1%/年利息的话，年回报8%就很好了，千万别听隔壁小马赚了很多钱的那些故事，哪怕那故事是真的。” — 段永平（来源：投资逻辑篇，2019-05-17）
“‘持有’在每个时点确实是等于’买入’的，机会成本就是这个意思！” — 段永平（来源：投资逻辑篇）
“想10年后，相对于你自己的机会成本。” — 段永平（来源：投资逻辑篇，2020-11-02）
🔗 关联节点
上游概念（理解这个概念的前提）： 内在价值 · 能力圈 · 买入逻辑