Reverse bill of materials

What it is: build the bill of materials for a thing, then run it backwards off mandatory regulatory filings to find what it actually costs and who actually captures the margin.

When to reach for it

When a company's story and a company's economics might not match — and there is a filing that has to be true. Reach for it when the number everyone repeats came from a press release.

The steps

Build the forward BOM. What is this thing physically made of? Major subsystems, then parts.
Name the supplier for each line. Who actually makes it. This is where concentration shows up.
Go to the filings, not the feed. SEC EDGAR full-text search — 10-Q, 10-K, S-1. His words: "filings that are mandatory and are due to scrutiny."
Run it backwards. Segment revenue and cost of revenue against your BOM lines. The gap between what a part costs and what the system sells for is the answer.
Ask who is a single point of failure. If one supplier appears on every line, that is the story.

Worked example

Applied to NVIDIA (Moonshots #284 0:00) → the panel holds NVIDIA as an index of the era. The method asks a different question: "why should I start looking at financing coming from anywhere except going to NVIDIA? They have a ton of cash, they have the technology, they have the interest." Then it surfaces TSMC as the single point of failure under the whole stack — a conclusion the panel never reaches, arrived at by looking at parts instead of price.
Applied to launch → the idiot index piece, published 2026-07-08, GForce's best-performing post to date. Same method, different object.

Where it fails

It cannot price private companies. No filing, no method. SpaceX before the S-1 is guesswork and should be said as guesswork.
Segment reporting is coarser than a BOM. You will often get "Data Center: $89.0B" and no way to split it. Do not manufacture the split.
It says nothing about demand. A perfect BOM tells you what a thing costs and nothing about whether anyone will buy it. That is the downstream half → see the ## Downstream section on every entity page.
⚠️ It invites false precision. On tape, "89% versus 44" was not a growth rate. Run verify-first on every figure the method produces.

Where I learned it

Hardware. You cannot ship a system without knowing what it is made of, and once you have costed a real BOM you stop believing headline numbers about anything.