US stock indices fall; Nasdaq 100 breaches key moving average

US stock indices moved lower in Monday's session. The S&P 500 posted a slight decline, while the NASDAQ Composite dropped 0.33% and the NASDAQ 100 fell 0.65%.

All three indices had closed at record highs last Tuesday, then fell on Wednesday and Thursday. Friday's bounce strengthened the technical outlook, but Monday's losses have eroded some of that bullish momentum.

The rising 100-hour moving average remains the key reference point. Last week, each index's low held at or near that moving average, providing buyers a level to defend and maintaining their control.

On Monday, however, the technical picture began to diverge:

• S&P 500: Its 100-hour moving average sits at 7738.18. Monday's low touched 7802.58, and the index now trades around 7809.96. Buyers retain control as long as the price stays above that moving average.

• NASDAQ Composite: The 100-hour moving average is at 27151.12. Monday's low hit 27240.47, and the index is currently near 27275. The bullish bias is still intact, though the distance above support has shrunk.

• NASDAQ 100: The 100-hour moving average is at 30689.21. Monday's low dipped below that level to 30633.80, giving sellers a slight technical edge. If the price remains below the moving average, sellers will have more short-term control. A move back above it would weaken that bearish signal.

The message for traders is clear: a single down day does not necessarily shift the technical bias. What matters is where the price stands relative to support. The S&P 500 and NASDAQ Composite continue to hold above their key moving averages. The NASDAQ 100 has broken below its support, and sellers must now keep the price beneath it.