---
title: "Earnings averaged over only a few months: what a short window can hide"
url: https://firstpassmemo.com/flags/earnings-averaged-over-short-period/
updated: 2026-10-07
publisher: FirstPass Memo (hello@firstpassmemo.com)
---

Red flag explained · Trend

# Earnings averaged over only a few months: what a short window can hide

Short answer: An average over fewer than 12 months can hide seasonality, a launch spike or a recent peak. A price set on the best three months gives a shorter payback on paper than the year behind it supports. Ask for 12 to 24 months of monthly figures and work out payback on the full year.

Updated 7 October 2026 · Checker rule SHORT_PERIOD

## When the checker raises it

Raised as medium severity when the listing says its figures cover the past or last N months, with N under 12.

## Why it matters

Most small online businesses are seasonal. Gift stores peak in November and December, tax and finance content in spring, and many business tools dip in summer.

Some marketplaces let sellers choose the averaging window. A seller who picks three months has usually picked their best three.

## A worked example

Composite example, not a real listing

Online store selling winter knitwear Asking price: $30,000 Average monthly profit: $1,900 over the last 4 months Average monthly revenue: $9,000 Business age: 3 years Owner hours: 8 hours per week

Traffic or revenue sources typed in: Paid 60%, Organic search 20%, Direct 20%.

What the red-flag checker (https://firstpassmemo.com/checker/) returns: payback of 15.8 months on average monthly profit, and this flag:

Medium Earnings averaged over only 4 months

A short window can hide seasonality or a recent peak.

Ask: Can you share 12 to 24 months of monthly revenue and profit, not only the recent average?

The same example also raises: No connected data source mentioned (https://firstpassmemo.com/flags/no-connected-data-source/), Concentration not disclosed (https://firstpassmemo.com/flags/concentration-not-disclosed/).

## What to check

- Ask for 12 to 24 months of monthly revenue and profit.

- Ask why the listing uses this window.

- Compare the same months a year earlier if the business is old enough.

## Questions to send the seller

- Can you share 12 to 24 months of monthly revenue and profit, not only the recent average?

- Can you share a monthly P&L for the last 24 months, with revenue and every cost line?

- Can you show the same month last year, so seasonality can be separated from decline?

- Are there one-off items in the period, such as a large sale, a refund or a paused cost, that move the average?

## Related flags

- Last month below the average (https://firstpassmemo.com/flags/last-month-profit-below-average/)

- Monthly and annual revenue disagree (https://firstpassmemo.com/flags/monthly-revenue-does-not-match-annual/)

- All red flags explained (https://firstpassmemo.com/flags/)

## Useful next

- How to calculate payback (https://firstpassmemo.com/guides/how-to-calculate-payback-on-an-online-business)

- Free red-flag checker (https://firstpassmemo.com/checker/): paste a listing and see which flags it raises.

The checker is a set of plain rules, not an AI model, and its flags are prompts for questions, not verdicts. Composite examples are invented. Informational screening only, not investment, legal or tax advice.

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FirstPass Memo is informational screening, not investment, legal, tax, accounting or valuation advice, and not an audit. Seller figures are not independently verified. HTML version: https://firstpassmemo.com/flags/earnings-averaged-over-short-period/