Broker business size
The "size" of an insurance broker business often is measured by the recurring revenue made through commissions being payed by the insurer. This inlcudes both first time commissions and recurring commissions.
Another metric is the volume of contracts, measured in different ways depending on the line of business (see post "broker's revenues" - coming soon). For example, P&C volume is measured by the premiums to be paid by the policy holder.
In Germany, the term "Jahresnettoprämie" (JNP) is being used to express the premium payed deducted by the insurance tax amount, that currently is 19% of the JNP.
Insurer business size
From an insurers point of view this "Jahresnettoprämie" equals the gross written premium (GWP). This is the sum of premiums written witout insurance tax before deducted by ceded reinsurance premiums. This is a metric for determining the size of business of an insurer.
Don't mix these terms up! Make sure you are talking about the same thing. This could be easily done by referring the the respective point of view when talking about these metrics: Broker or insurer. Otherwise the terms can be misleading or confusing.
For example, a public listed FinTech in Germany has published the amount of written premiums of their broker clients (Jahresnettoprämie (JNP)) using the term net written premiums (NWP). Instead, they rather had to apply the term gross written premiums to express their metric correctly.