Investor Lenses

What a lens is

A lens is a reasoning procedure: a fixed, ordered set of questions plus explicit veto rules, distilled from one investor's publicly published methodology. It is applied after the evidence exists — it does not gather data and does not care where the data came from.

The value of a lens is that it is opinionated and therefore falsifiable. A lens tells you, before you look at the answer, which signals it ranks first and which facts make it walk away. Two lenses disagreeing on the same evidence is the product, not a bug: the disagreement localizes exactly which assumption the decision rests on.

What a lens is NOT

• Not investment advice. Every lens output is an analytical exercise.
• Not the named person's opinion. Each lens is a reconstruction, in our own words, of a methodology that investor has described publicly. It is not written by them, not endorsed by them, and may diverge from what they would say today.
• Not a universal truth test. A lens verdict is conditional on the lens. "Fails the Graham lens" and "bad investment" are different statements.
• Not a ranking of masters. No lens is more correct than another; each has a domain where it is sharp and a domain where it is reliably wrong.

The five-step run

1. Freeze the evidence. Write down what is known before choosing the lens — financials, prices, disclosures, timelines. A lens applied to evidence collected after the lens was chosen is circular.
2. Choose by the situation, never by the answer you want. Use the selection table below. If you are picking the lens because you already know its verdict, stop.
3. Walk the priority signals in order. Each lens orders its signals for a reason. Do not jump to the signal you have the best data on.
4. Hit a hard disqualifier → stop and report the veto. Disqualifiers are not weighted against positives. They end the run under that lens.
5. Run the misuse check, then emit under the output contract. Every lens file lists the regimes where it fails. State explicitly whether the current case sits in one of them.

Lens index

Choosing a lens

Stacking protocol

Stacking is where lenses earn most of their value, but only under discipline.

• Two or three lenses. Never more. Beyond three the output degenerates into a survey and the disagreements stop being legible.
• Choose lenses that can actually disagree. Buffett + Duan Yongping mostly agree by construction; that stack is decoration. Buffett + Chanos, or Feng Liu + Munger, produce real tension.
• Run each lens independently before comparing. Do not let lens 2 read lens 1's verdict. Cross-contaminated lenses collapse into one lens.
• Classify every disagreement into exactly one root cause:
  • Horizon — same facts, different holding period (10-year certainty vs. next two quarters).
  • Caliber — the two lenses are measuring different quantities (owner earnings vs. reported net income; EV vs. market cap).
  • Risk preference — same expected value, different tolerance for the left tail.
  • Information — one lens needs a fact nobody has. Say which fact.
• Never average the verdicts. A 2-to-1 split among lenses is not evidence of anything; lenses are not voters and they are not independent samples. Report the split and its root cause instead.
• Report the losing lens's strongest point verbatim. If it cannot be stated fairly, the stack was not run honestly.

Anti-patterns

• Lens shopping — running lenses until one agrees with the pre-existing conclusion, then reporting only that one. If a lens is run, it is reported.
• Lens as authority — "Buffett would buy this" is a claim about a person and is unsupportable. "Under a quality-franchise lens, this passes the moat test and fails the price test" is a claim about a procedure and is checkable.
• Biography instead of procedure — quoting temperament, anecdotes or life story in place of walking the signal list.
• Silent disqualifier — noticing a hard veto and continuing to score anyway because the rest of the picture is attractive.
• Lens applied out of market — a US-designed lens dropped onto an A-share name without adjusting for what the disclosure regime actually reveals. Each lens file carries a market-fit note; read it.
• Retrofitting the evidence — going back to collect exactly the data the chosen lens rewards, after choosing the lens.

Output contract (binding on every lens)

Any output produced under this skill must contain, in this order:

1. Lens name and one-line statement of what it optimizes for.
2. Verdict, explicitly framework-conditional — phrased "under this framework, …", never as a flat assertion about the security.
3. The ordered signal walk — each priority signal, the evidence found, and whether it passed. Missing evidence is written as missing, never inferred.
4. Disqualifier check — every hard veto listed and marked triggered / not triggered / unknown.
5. Misuse check — whether the current case sits in a regime where this lens is documented to fail.
6. Falsifiers — the two or three observations that would flip the verdict, each concrete enough that someone could go check it.
7. Confidence with its limiting factor — "medium, limited by the absence of segment-level disclosure", not a bare number.
8. The standing disclaimer: this is an analytical framework, not investment advice, and the verdict is conditional on the framework used.