US equity indexes fell in midday trading on Friday, with the S&P 500 reportedly heading for a fifth consecutive week of declines, as investors navigate mounting economic uncertainty.

The Nasdaq Composite declined 0.3% to 17,637.4, with the S&P 500 down 0.5% to 5,636.1 and the Dow Jones Industrial Average 0.4% lower at 41,782.2. All sectors, except communication services, were in the red intraday, with materials the steepest decliner.

FedEx (FDX) shares slumped past 8% intraday, the worst performer on the S&P 500. The company overnight lowered its fiscal 2025 outlook for adjusted earnings and softened its revenue forecast. Loop downgraded FedEx to sell from hold and lowered its price target to $221 from $283, while JPMorgan cut the price target to $280 from $323.

NIKE (NKE) shares dropped 5.7% intraday, the steepest decliner on the Dow, after the firm reported lower fiscal Q3 earnings and revenue.

US economic growth will likely slow in line with the updated forecasts in the Summary of Economic Projections, New York Federal Reserve President John Williams said Friday at the Macroeconometric Caribbean Conference.

"I expect GDP [gross domestic product] growth this year to step down from last year's pace in part because of a slowdown in labor force growth due to lower immigration rates," Williams said.

While inflation expectations in the near term have been rising due to concerns about the impact of tariffs, those effects are expected to moderate over time based on New York Fed data, Williams added.

Meanwhile, US Treasury yields traded mixed intraday, with the 10-year yield up 1.7 basis points to 4.25% while the two-year rate fell 1.7 basis points to 3.94%. Both maturities are heading for a decline compared with a week ago, reflecting in part the market's growth concerns.