Audit Firm Selection: Big Four, Mid-Tier and Sector Specialists

The selection of a reporting accountant is one of the earliest and most consequential pre-IPO decisions. Big Four firms command a premium because of their global resources for multi-jurisdiction audits and their institutional credibility with HKEX and the SFC. For companies with significant international operations, the Big Four are often the default choice because no mid-tier firm can match their multi-country audit coverage. Mid-tier firms offer greater partner attention — a mid-tier audit partner may personally lead the engagement, whereas a Big Four partner oversees a team of managers and associates. For smaller IPOs (below US$200 million), the cost differential is material: Big Four audit fees can be 2-3x mid-tier fees. Sector specialist firms — firms with deep expertise in specific industries like shipping, property, or natural resources — may provide more relevant technical accounting guidance than a generalist Big Four team. The key criterion is not brand but HKEX acceptance: the audit firm must be registered with and recognised by HKEX for IPO reporting accountant work.