ISVWorld calculates sizing estimates for private companies based on a number of proxies datapoints we can find for any company. Datapoints might include the total number of employees, employees per company location, size of funding rounds, news and press releases that contain size indicators, and more.
We calculate multiple size estimates, take out statistical outliers, and base our size estimates on consistent indicators only. ISVWorld size estimates are always ranges, for example, 5-10M$, 10-25M$ etcetera.
In case of fast-growing companies, public datapoints usually lag actual company size and as a result, our estimates are sometimes lower than actuals.