Actionable insights — TransDigm: Mini-Monopolies at 30,000 Feet

1. Test pricing power with three conditions, not with brand or margin

1. Is the product mission-critical — can the customer operate without it? (Better still: is it legally required?)
2. Is there almost no competition for this specific item, and what stops a new entrant?
3. Does the product represent a trivial share of the customer's total cost? Compute the actual ratio rather than asserting it.
4. Only when all three hold does an annual price increase go through unopposed. Two out of three is not enough.

• The share-of-cost ratio drifting up. Repeated price rises eventually make the item visible in the customer's budget — that is the mechanism's own expiry date.

2. Find behavioural proof that the customer is price-insensitive

1. Do not infer insensitivity from margins — margins are the result you are trying to explain.
2. Look for customer behaviour that only makes sense if price is irrelevant: not pursuing refunds, not tendering, not switching after an increase.
3. Compare that behavioural threshold with the company's actual average selling price.
4. If the threshold is above the price, price increases have room to run.

• Procurement reform at a large customer. The anecdote describes a habit, and habits are exactly what a cost-cutting drive targets.

3. Check a serial acquirer's record against the base rate before believing it

1. Establish the base rate: roughly 70% of acquisitions destroy shareholder value.
2. Count the deals and ask what the claimed hit rate implies. A perfect record across dozens of deals is statistically extraordinary — 0.3^82 by chance.
3. Treat that as a prompt to verify rather than to admire: who computed the returns, on what definition, and was it audited by a credible outsider?
4. Look for an independent corroborating signal — an award judged by peers, a competitor's testimony, or a third-party analysis.

• Self-reported deal returns. The figure comes from management and its own advocate; the corroboration is qualitative, not an audit.

4. Weight the testimony of a competitor you acquired above any other source

1. Look for cases where a direct rival came inside the business — through acquisition, a hire, or a partnership.
2. Their assessment is the least contaminated evidence available: they had every incentive to believe the model was replicable, and they had tried.
3. Weight a reversal of view (they tried to copy it and could not) more heavily than any management presentation.

• The obvious selection effect — you rarely hear from the rivals who succeeded, because they were not acquired.

5. Separate razor from razorblade, and value them differently

1. Split revenue into the original sale and the replacement stream, and get the margin on each.
2. Estimate the installed life of the product — the longer it is, the larger the aftermarket relative to the original sale.
3. Ask why nobody enters the replacement market: in shrinking, ageing fleets the prize is falling while the approval cost is not, so entry is unattractive by construction.
4. Value the aftermarket as recurring revenue and the original sale as cyclical, not as one blended business.

• A regulatory route around the monopoly. PMA approvals let a third party make an approved replacement, and their use "has increased in recent years."

6. Treat approval cost as a moat — and measure it by how long incumbents have survived

1. Identify the regulatory approval a new entrant would need, and estimate its cost and elapsed time.
2. Test the barrier empirically: how old are the incumbents in this niche? Longevity is the observable proxy for entry difficulty.
3. Prefer the boring components: the more mundane and less performance-differentiating the part, the less anyone bothers to attack it.
4. Check whether a regulator could create a bypass — that is the barrier's single point of failure.

• The bypass being the same regulator. PMA is an FAA programme — the body that built the barrier also runs the route around it.

7. Convert a pass into a standing order by naming the price

1. Complete the full quality work even when you expect to decline — it is reusable the moment the price moves.
2. State the reasons for the pass in order of importance, separating structural objections (size, leverage) from price.
3. Convert the price objection into a specific multiple, then into a specific share price, and state the distance from today.
4. Record it so the decision is triggered by the market rather than remade under pressure.

• The article's own counter-argument: TransDigm "has always been expensive but kept generating shareholder value." A multiple-based trigger can keep you out of a business whose multiple never mean-reverts.

8. Read a negative ROE before treating it as a failure

1. When return on equity is negative, check whether the denominator is negative rather than the numerator.
2. Negative equity from debt-funded buybacks and special dividends is a capital-structure choice, not unprofitability.
3. Switch to return on invested capital, which is unaffected by the distinction, and judge on that.
4. Then judge the leverage on its own terms — interest coverage and net debt to EBITDA — rather than through the ROE artefact.

• Debt raised to fund a distribution rather than an acquisition — flagged here as the one management decision that "doesn't make much sense in our opinion."