What it means
Financial statements are published on a fixed calendar, but decisions are made continuously. If a company's year ends in December and it is now September, the last audited figures are nine months stale, and the year-to-date numbers cover only part of a seasonal cycle.
Trailing 12 months solves both problems by rolling the window forward each period. The measure always covers exactly four quarters, so seasonal peaks and troughs each appear once, and it always ends at the most recent reporting date available.
The standard construction takes the last full financial year, adds the current year to date, and subtracts the equivalent year-to-date period from the prior year. That third step is what people forget, and leaving it out double-counts several months of trading.
TTM figures are the default in valuation and lending. Acquirers quote multiples of TTM revenue or TTM EBITDA, and lenders test covenants against trailing twelve month earnings, because both want a full annual cycle measured as close to today as possible.
The main limitation is that TTM looks backwards through a fixed window, so a genuine step change gets diluted. A business that doubled in size four months ago will show a TTM figure sitting somewhere between the old and new run rates, which is why fast-growing companies are often also valued on an annualised recent-quarter basis.
In practice
Real-world examples.
Example
A private equity buyer values a logistics target on 6.5 times trailing 12 month EBITDA of $2,800,000, giving an enterprise value of $18,200,000. Using the audited year-end EBITDA of $2,400,000 would have priced the business $2,600,000 lower.
Example
A bank tests a leverage covenant every quarter against trailing 12 month EBITDA rather than the audited annual figure. This catches deterioration within months instead of waiting up to a year for the next set of statutory accounts.
Example
A software company reports trailing 12 month recurring revenue in every board pack alongside annualised recurring revenue. The trailing figure shows what was actually billed, while the annualised figure shows the current run rate, and the board watches the gap between them.
Formula
Calculation
TTM = Last Full Financial Year + Current Year to Date - Prior Year Same Period
A distribution business has a December year end, and it is now the end of September. Its audited revenue for last financial year was $12,000,000. Revenue for the nine months to September this year is $10,200,000, and revenue for the same nine months last year was $8,700,000.
Step 1: Start with last full year = $12,000,000
Step 2: Add current year to date = $12,000,000 + $10,200,000 = $22,200,000
Step 3: Subtract prior year same period = $22,200,000 - $8,700,000 = $13,500,000
Trailing 12 month revenue is $13,500,000, covering October last year through September this year. Comparing that with the $12,000,000 full year shows growth of $1,500,000, or 12.5%, and if a buyer applied a 1.4 times revenue multiple the valuation would be $18,900,000 rather than the $16,800,000 the stale year-end figure would have produced.Case study
Seen in the real world.
This is a fictional and illustrative example. Aldergate Distribution, an invented wholesaler, went to market with a December year end showing $12,000,000 of revenue, and the first indicative offers were built off that number at 1.4 times revenue, or $16,800,000.
The company's adviser rebuilt the pack on a trailing 12 month basis to the end of September. Adding the $10,200,000 achieved in the first nine months and removing the $8,700,000 from the same nine months a year earlier produced trailing revenue of $13,500,000, which supported an $18,900,000 valuation on the same multiple.
The buyer accepted the logic but insisted on quality of earnings work to confirm that the extra $1,500,000 was genuine trading rather than pulled-forward orders or a one-off contract. That review cost the illustrative seller around $40,000 and comfortably paid for itself, which is the practical lesson: a TTM figure only helps if it survives scrutiny.
Watch out
Common mistakes.
- Forgetting to subtract the prior year comparable period. Adding year to date onto a full year without removing the overlap counts several months twice and badly overstates the result.
- Building a TTM figure from months prepared on inconsistent bases. Mixing audited and unaudited periods without adjusting for year-end accruals produces a number nobody can rely on.
- Using TTM as a forecast. It describes twelve months that have already happened and carries no assumption about what comes next.
Questions
People also ask.
Is TTM the same as LTM?
Yes, trailing twelve months and last twelve months describe exactly the same window, with the two labels used interchangeably.
Why do lenders prefer TTM to the statutory year?
Because it is refreshed each quarter, so covenant tests reflect recent trading rather than results that may be nearly a year old.
When is TTM misleading?
When a business has recently made an acquisition, changed pricing or gone through a step change in volume, since the older months in the window no longer represent how the company now operates.
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