Synopsys Jumps 12.86% On Technical Rebound After 35.84% Plunge

Synopsys (SNPS) surged 12.86% on September 18, 2025, closing at $480.11 with a trading range of $448–$483.24 on elevated volume of 8.2 million shares. This robust recovery follows a period of high volatility after the stock plummeted 35.84% on September 10, establishing critical technical reference points for analysis.
Candlestick Theory
A decisive bullish engulfing pattern emerged on September 18, engulfing the prior three sessions' range and closing near the session high. This signals strong demand after consolidation near the $425 support level, which held through September 15–17. Resistance is now evident at $483–$500, aligning with September's pre-gap prices. A sustained break above $485 would target the $520 psychological barrier.
Moving Average Theory
The 50-day moving average ($445) recently crossed below the 200-day ($520), confirming a bearish long-term structure. However, the September 18 rally pushed the price above the flattening 50-day average, suggesting nascent short-term strength. The 100-day average ($490) and 200-day average ($520) remain critical overhead resistances. Confluence exists at $485–$490, where the 50-day and price resistance converge.
MACD & KDJ Indicators
MACD (12,26,9) triggered a bullish crossover on September 18 as the histogram turned positive for the first time since early September. Simultaneously, the KDJ stochastic (%K=82, %D=75) exited oversold territory with a bullish crossover while approaching overbought conditions. Momentum divergence preceded the rally: RSI and MACD registered higher lows against price’s sideways action at $425 support, foreshadowing the rebound.
Bollinger Bands
Bollinger Bands (20-day, 2σ) contracted sharply during the September 10–17 consolidation, with bandwidth narrowing 35% before the September 18 breakout. The price closed above the upper band ($470), indicating potential short-term overextension. The band expansion confirms renewed volatility bias. A mean-reversion pullback toward $460 (mid-band) would offer a healthier entry point if volume supports it.
Volume-Price Relationship
Distribution occurred on September 10's historic selloff (21.1M shares), validated by the failure to reclaim $600. Accumulation emerged on the September 11 rebound (15.3M shares) and the latest session's breakout (8.2M shares—second-highest volume in 3 months). The volume profile shows anchored support at $425–$430, where multiple high-volume sessions established a base. Sustainability requires follow-through volume >5M shares.
Relative Strength Index (RSI)
The 14-day RSI (now at 65) rebounded from oversold (29) on September 17. While approaching overbought territory (>70), no bearish divergence is present. Caution is warranted as RSI at current levels coincided with reversals in early September. The rally’s sustainability hinges on RSI maintaining momentum without forming lower highs against ascending prices.
Fibonacci Retracement
Using the September 9 high ($604.37) and September 10 low ($387.78), key retracement levels are: 38.2% ($480), 50% ($496), and 61.8% ($512). The September 18 close precisely at the 38.2% level creates immediate technical resistance. Confluence exists at $496–$500 (50% retracement + 100-day moving average + psychological resistance). Acceptance above $512 would invalidate the bearish structure established in September.
Confluences reinforce $480–$485 as a tactical pivot: A breakout above the 38.2% Fib with volume could target $500, while failure may retest $460. Divergences were resolved with recent momentum confirmations, though overbought risks near $500 warrant monitoring. Probabilistic bias leans cautiously bullish if $460 support holds.