The S&P 500, Nasdaq Composite and Nasdaq 100 are under technical pressure. Key support levels could offer a lifeline, but buyers need to prove they can hold them.The broader US stock indices are trading near their lows for the day. If the indices were ships on the water, they would be taking on water.Broken moving averages have tilted the technical bias toward the sellers. However, support targets loom below that could help steady the ships. The question is whether buyers can lean against those levels and force a recovery—or whether sellers punch another hole in the hull.S&P 500: A key support zone comes into viewThe S&P 500 has fallen below its 100-hour moving average at 7754 and 200-hour moving average at 7714. Those breaks give sellers more control and turn the moving averages into resistance on a recovery.The next key downside focus is the rising 100-day moving average at 7603, which sits inside a swing area between 7573 and 7617.That combination makes this an important zone for buyers. Holding it could give them a platform for a bounce. Break below 7573 and stay below, however, and the door opens for further selling momentum.For now, support is approaching. Buyers still need to show up.Nasdaq Composite: The broken 100-day moving average defines riskThe Nasdaq Composite tested its 200-hour moving average yesterday, but fell sharply at today’s open and broke below its 100-day moving average at 26265.87.That 100-day moving average now becomes a nearby risk-defining level. Stay below it and sellers retain the technical advantage. Move back above and stay above, and some of the immediate downward pressure would ease.Without that recovery, the next downside targets are the September low at 25831.74, followed by the 38.2% retracement at 25036.33 and the rising 200-day moving average at 24980.37.The retracement and 200-day moving average form another important support zone. But the first job for buyers is to reclaim the broken 100-day moving average. Until then, sellers remain in control.Nasdaq 100: Buyers get a chance against a swing areaThe Nasdaq 100 gapped below its 100-day moving average at 29589.57 at the open and extended to a session low of 28962.36. That brought the index within about nine points of the upper boundary of a swing area between 28822 and 28953.This is where buyers have an opportunity to make a stand.If the index can hold that swing area, a recovery toward the broken 100-day moving average becomes a possibility. Getting back above **29589.57—and staying above—**would give buyers more control from a technical perspective.Conversely, a break below 28822 would weaken that recovery scenario and expose the 38.2% retracement of the rally from the 2026 low at 28108.The distinction matters: holding support can start a bounce. Reclaiming the broken moving average would strengthen the case that buyers are taking back control.Support could steady the ships. The bias remains bearish.The broader indices are sinking, but each has identifiable support ahead that could help slow the selling.Support, however, is a place to watch for a response. It is not a guarantee that the decline is over. Buyers need to hold those levels and then reclaim the technical levels broken on the way down.Until that happens, the bias remains more bearish.In the video above, I take a look at the three broader US stock indices, the support levels that could steady the ships, and what buyers need to do to take back control. This article was written by Greg Michalowski at investinglive.com.