QuinStreet (QNST) shares plummeted 12.42% in Thursday's trading session, significantly extending the pre-market losses following the company's mixed third-quarter earnings report and maintained full-year outlook. The digital marketing firm's performance, while showing year-over-year growth, failed to meet investor expectations.

QuinStreet reported adjusted earnings per share of $0.21 for the quarter, surpassing analyst expectations of $0.20 and marking a substantial 250% increase from the same period last year. However, the company's quarterly sales of $269.84 million fell short of the consensus estimate of $270.35 million, albeit by a narrow margin of 0.19%. Despite the miss, sales still showed a robust 60.06% growth compared to the previous year.

Adding to investor concerns, QuinStreet maintained its full fiscal year 2025 revenue outlook of $1.065 billion to $1.105 billion, aligning with the consensus of $1.09 billion. The decision not to raise guidance, coupled with the slight sales miss, appears to have significantly disappointed investors hoping for more aggressive growth projections. This combination of factors likely contributed to the sharp 12.42% decline in QuinStreet's stock price during the trading session, as the market reacted more severely than initially anticipated in pre-market trading.