Supermicro Stock Dives as Accounting Firm Resigns

Major U.S. equities indexes traded in positive territory for much of the session on Wednesday before losing ground in the afternoon and closing slightly lower.

The see-saw mid-week trading day came as the latest gross domestic product (GDP) figures showed an unexpected sequential downtick in economic growth during the third quarter. Although sluggishness in the housing market dragged down the economy’s performance, one bright spot was consumer spending, which posted its strongest growth rate since the first quarter of 2023.

The S&P 500 closed with a daily loss of 0.3%. The Dow slipped 0.2%, while underperformance in the tech sector contributed to a drop of 0.6% for the Nasdaq.

Super Micro Computer (SMCI) shares plummeted 32.7%, surrendering nearly a third of their value and enduring the steepest daily drop of any S&P 500 stock. The plunge came after a regulatory filing revealed that accounting giant EY resigned from its role as auditor for the server and data storage provider. Supermicro’s accounting practices have been under the microscope since short seller Hindenburg Research published a report in August accusing the firm of “manipulation.” Supermicro said it disagreed with EY’s decision but stressed that it would take the concerns raised by the accounting firm seriously.

Shares of Qorvo (QRVO), which produces power and radio-frequency semiconductors, tumbled 27.3% as the company reported an unanticipated loss for its fiscal second quarter of 2025. The company also cautioned that softness in its business could persist for the remainder of the fiscal year, citing an “unfavorable mix” related to customers opting for entry-tier Android 5G smartphones at the expense of mid-tier models.

Business IT solutions provider CDW Corp. (CDW) reported lower-than-expected sales and profits for the third quarter, and its shares dropped 11.3% on Wednesday. The uncertain economic environment led to restrained spending, project delays, and weak hardware demand among corporate and small-business customers, weighing on CDW’s performance.

Wednesday’s top performance in the S&P 500 belonged to shares of wearable device and GPS navigation provider Garmin (GRMN), which surged 23.2%. The gains came after Garmin reported higher-than-expected sales and profits for the third quarter, with year-over-year sales growth throughout all its business units. The company also lifted its full-year sales and profit guidance, anticipating its momentum will continue into the critical holiday season.

Shares of packaging manufacturer Smurfit WestRock (SW) jumped 12.0% after the company released its first earnings report to reflect combined results following the merger between Smurfit Kappa and WestRock, which closed in July. Although results fell short of top- and bottom-line estimates, the company stressed that merger-related expenses contributed to its net loss for the quarter. Smurfit WestRock also highlighted its sales performance, driven by the addition of WestRock and solid volumes in corrugated packaging, suggesting it is well-positioned for additional growth.

FMC Corp. (FMC) shares added 10.7% after the maker of insecticides and other crop-protection products topped third-quarter sales and profit forecasts. Despite a challenging environment in the agricultural industry, robust sales growth in North America, cost-savings initiatives, and the sale of its Global Specialty Solutions (GSS) business helped underpin FMC’s strong performance.