Key Takeaways

Major U.S. equities indexes dropped Wednesday as Congressional debates about a Republican tax and spending bill underscored concerns about the deficit and the country's fiscal trajectory.

Meanwhile, an uptick in long-term Treasury yields added to questions about the sustainability of the recent stock-market rally. The S&P 500 lost 1.6% in the midweek trading session. The Dow dropped 1.9%, while the Nasdaq ended 1.4% lower. Read Investopedia's full coverage of today's trading here .

Shares of credit score provider Fair Isaac ( FICO ) plunged 16%, falling the furthest of any stock in the S&P 500 for a second straight session. The move lower followed comments from Bill Pulte, director of the Federal Housing Finance Agency, who singled out the pricing of FICO’s credit evaluations in a conversation about lowering mortgage origination costs. Shares of fellow consumer credit reporting agency Equifax ( EFX ) lost 6.7%.

AES Corp. ( AES ) shares also extended a string of recent losses, dropping 9.9% on Wednesday. Jefferies analysts downgraded the renewables-focused energy producer’s stock to “underperform” on Tuesday, citing a cautious view on the company’s financial health and market position.

Moderna ( MRNA ) said it has withdrawn an application for the approval of a combination COVID and flu vaccine, and shares of the biotech firm dropped 7.8%. The losses mark a reversal from a recent uptick for Moderna’s stock, which gained steam as the Food and Drug Administration announced new guidelines for COVID vaccine boosters .

Palo Alto Networks ( PANW ) shares slid 6.8% after the cybersecurity firm released financial results for its fiscal third quarter. Sales and profits edged out expectations , reflecting progress in the firm's "platformization" strategy, which involves bundling products to encourage adoption. However, gross margins came in shy of forecasts, and operating expenses were above last year’s levels.

Shares of Google parent company Alphabet ( GOOGL , GOOG ) rose nearly 3%, securing the day's top performance in the S&P 500. The gains followed the tech giant’s Google I/O conference keynote and its rollout of an artificial intelligence (AI) search mode across the U.S. Several analysts responded favorably, praising Alphabet’s cross-product AI integration along with its evolving strategy as the search landscape shifts.