Marqeta, a leading modern card issuing platform, saw its stock price plummet over 30% in after-hours trading on Monday after reporting disappointing third-quarter earnings and providing weak guidance for the fourth quarter.

For Q3 2024, Marqeta reported an adjusted loss of $0.06 per share, slightly worse than analysts' expectations of a $0.05 loss per share. The company's revenue grew 18% year-over-year to $128 million but narrowly missed the consensus estimate of $128.09 million.

While Marqeta's total processing volume increased by a robust 30% year-over-year to $74 billion, and gross profit rose 24% to $90 million, the company's guidance for the fourth quarter fell short of expectations. Marqeta projected net revenue growth of just 10-12% and gross profit growth of 13-15% for Q4, significantly lower than Wall Street's expectations.

CEO Simon Khalaf cited "heightened scrutiny of the banking environment and specific customer program changes" as factors impacting the weaker-than-expected fourth-quarter outlook. The company expects its adjusted EBITDA margin to be between 5-7% for Q4.

Investors reacted negatively to the disappointing results and guidance, with Marqeta's stock plunging over 31% in after-hours trading on Monday. The steep decline highlights concerns about the company's slowing growth prospects and the potential impact of increased regulatory scrutiny in the fintech and banking sectors.