Natera is trading 13.65% lower at $337.46 in after-hours trading, with the decline appearing primarily tied to risk-off market conditions. - Shares closed at $390.79 on September 23, 2026. - The Nasdaq was down 1.10% and the S&P 500 was down 0.74%. - No new earnings release, downgrade, or company-specific announcement was identified after the close. The September 22 Japan regulatory approval remains supportive but predates this reversal.