Question

How does a company determine a materiality level for expense disclosure?

Answer 1

There would be trivial materiality as well as overall materiality

Trivial materiality would be for a transaction (eg: rent expenditure) and overall materiality would be for all group of transactions as a whole.(all expenses)

In auditing terms, determining the level of materiality requires that an appropriate base percentage be decided on. The most commonly used base in auditing is net income (earnings / profits). Ranging from 5 to 10% most of the time but in some cases vary as per industry standards.

In your question the materiality level would depend on the nature of the company but a simple assumption of 5 % would cover most of the cases.