BRUNCH

No room for a fifth? The Big Four’s iron grip on STI audits

Every company in the index uses PwC, KPMG, EY or Deloitte. Why can’t mid-tier rivals break in?

Renald Yeo
Published Fri, Jul 31, 2026 · 03:30 PM
    • The Big Four’s dominance in STI audits may not have pushed up fees, but this concentration has implications beyond competition, industry players say.
    • The Big Four’s dominance in STI audits may not have pushed up fees, but this concentration has implications beyond competition, industry players say. ILLUSTRATION: KEW KEAT BOON, BT; ADOBE STOCK

    [SINGAPORE] Thirty listed companies comprise The Straits Times Index (STI). But when those companies choose an auditor, the field narrows to just four names.

    Every current constituent appoints either PwC, KPMG, EY or Deloitte. Not one uses a mid-sized firm, generally referring to businesses with fewer than 1,000 employees.

    This is despite the fact that mid-sized firms, such as Baker Tilly, BDO and RSM Singapore, do audit other listed companies and compete for initial public offering (IPO) work.