3. Write-up: What are the differences between Big4 auditors and Non-Big4 auditors based on the answers of the first two questions? Please include at least two differences. What is the benefit or cost of this audit market structure? Tip 1: for the differences between Big 4 auditors and Non-Big 4 auditors, you can include different types of differences, including market share differences, the difference in client characteristics, how their market share differences or client characteristics differences change over time etc. Tip 2: audit market is an oligopoly with the four biggest audit firms dominating the market.