Here are the stocks that doubled in the third quarter

The third quarter saw major U.S. indices post solid gains, with the S&P 500 up nearly 8% and the Nasdaq over 11%, defying typical September weakness. Within this robust market, a select group of stocks, including AI connectivity provider Astera Labs, quantum computing firm Rigetti Computing, and data storage specialist SanDisk, achieved over 100% returns. While these companies capitalize on strong secular growth trends like AI and quantum computing, some, such as Astera Labs, carry LSEG consensus price targets indicating potential downside despite their recent strong performance and analyst bullishness.

Analysis

The third quarter of the year concluded with notable strength in major U.S. indices, with the S&P 500 gaining nearly 8% and the Nasdaq Composite advancing over 11%, defying typical September market weakness. Within this bullish environment, a select group of technology stocks delivered exceptional returns, including Astera Labs (ALAB), Rigetti Computing (RGTI), and SanDisk (SNDK), each gaining over 100%. Astera Labs, a beneficiary of the artificial intelligence trend, rallied approximately 124% in Q3, supported by strong second-quarter results and a bullish analyst outlook calling it an "AI pure play." However, a significant valuation discrepancy has emerged, as the LSEG consensus price target indicates a potential 3% loss, contrasting sharply with a single analyst's $215 target. Rigetti Computing, a pure-play quantum computing firm, surged over 150%, reflecting strong investor sentiment for the high-growth potential of an industry forecasted by Bank of America to reach $4 billion by 2030. SanDisk's near 154% gain was further propelled by a fundamental catalyst, as the company announced the start of production at a new plant in Japan to meet increased demand.

Key Decisions for Investors

• Investors should recognize that the triple-digit quarterly gains in these niche technology stocks, while impressive, significantly heighten valuation risks and the potential for sharp pullbacks.
• For Astera Labs, the divergence between the bullish Evercore ISI price target and the cautious LSEG consensus warrants close scrutiny; its 124% gain may have priced in much of the near-term AI-driven optimism.
• Positions in early-stage, high-volatility names like Rigetti Computing should be considered highly speculative, sized according to risk tolerance, and based on a long-term thesis on the quantum computing industry's development.
• The operational expansion at SanDisk provides a fundamental support for its rally, but investors should evaluate whether the benefits of increased production capacity are already fully reflected in its 154% quarterly stock appreciation.