According to Brand Finance’s valuations, Deloitte has overtaken PwC for first time in 10 years with a brand value up 42% to $29.7bn. Despite a torrid year, KPMG remains in the top 10 with a brand value of $13bn while BDO moves up a notch as 16th most valuable commercial services brand and a brand value up 14% to $3.3bn.

Brand Finance CEO David Haigh said: "In recent years we’ve seen a decline in dominance across the Big Four commercial services brands, with auditors criticised for failures in identifying irregularities across the books of major brands. Accountants simply must do more to restore trust in financial reporting."

Deloitte is also sector’s strongest brand, according to Brand Finance’s metrics. The report says Deloitte has taken the title of the world’s most valuable and strongest commercial services brand with a major portion of its brand value coming through its advisory service line, with its consulting revenue growing the fastest with double digit growth rates in each of the core capabilities: technology, strategy and operations and human capital.

PwC is the most valuable brand in both the assurance and tax service lines while EY saw the second highest brand value among the Big Four across all the three service lines, assurance, advisory and tax.

KPMG retains its spot as the fifth most valuable Professional Services brand but, Brand Finance said, ‘remains the most troubled among the Big Four, and has been impacted by controversies in 2018, including the widely-covered audit of the now defunct UK construction firm, Carillion’.