During 1990-1996, audit quality emerged as a function of auditor reputation and brand-name status, shaping investor perceptions and market responses to earnings surprises. The literature highlighted that industry specialization can bolster perceived credibility, and early models mapped the audit market in terms of demand, supply, price competition, and client switching, framing competitive forces as determinants of quality signals. It also linked audit quality to the information content of audits, influencing the pricing of new issues and the decisions of investors and underwriters.