Each week our technical scanner evaluates every stock in the S&P 500 and Nasdaq 100, tallying bearish and bullish indicator readings to surface potential short candidates. On 18 September 2026, the following five names generated the highest concentration of technical sell signals. A short candidate is a stock where the weight of technical evidence suggests further downside may be likely — though that is never a certainty.
Important risk notice: Short selling involves risks that are materially greater than buying a stock long. Losses on a short position are theoretically unlimited, margin requirements add financial leverage, and a sudden positive catalyst can trigger a sharp short squeeze. Treat every name below as a research starting point, not a trade recommendation, and always size positions according to your own risk tolerance.
1. Leidos (LDOS) – 13 technical sell signals
Price: $133.78 | Daily change: -3.88%
View the full technical analysis of Leidos
Leidos topped our bearish leaderboard on 18 September with 13 sell signals against just 3 bull readings, accompanied by a nearly 4% single-session decline. The drop came despite a busy news backdrop: the defence and technology contractor recently closed a $2.4 billion acquisition in grid infrastructure, a move some analysts have framed as a quiet play on AI-driven power demand. The company also secured an $875 million Navy network-modernisation contract extension covering more than 650,000 personnel — headline numbers that would ordinarily provide support.
Yet the price action tells a more cautious story. Leidos shares have struggled for much of 2026, weighed down earlier in the year by uncertainty around its health-IT contracts. While the stock attracted favourable valuation commentary and a Zacks Strong Buy upgrade as recently as late 2025, the technical picture has since deteriorated meaningfully. With 13 bearish signals now outpacing the 3 bullish ones by a wide margin, momentum appears to be working against the bulls in the near term.
The tension between solid fundamental newsflow and weak price action is precisely what makes this name interesting — and complicated — for short sellers. Any further positive contract announcements or an upward earnings revision could quickly reverse the technical picture, so risk management is essential.
2. Omnicom Group (OMC) – 13 technical sell signals
Price: $81.76 | Daily change: -5.03%
View the full technical analysis of Omnicom Group
Omnicom Group shed just over 5% on 18 September, producing the largest single-day loss among today’s five candidates. The advertising conglomerate matched Leidos with 13 bearish technical signals, though it carries slightly more bullish counterweights at 6, suggesting the picture is not entirely one-directional. The stock has delivered meaningful total returns over a five-year horizon, yet recent commentary points to valuation stretch, with at least one analyst suggesting the share price looks elevated relative to fundamentals even with healthy cash generation.
On the operational side, the numbers have been impressive: Omnicom posted year-on-year revenue growth of around 63% in the second quarter of 2026 and roughly 69% in the first quarter, figures substantially inflated by the integration of a major acquisition. The market’s muted reaction to those beats — the stock actually fell after the Q2 report — hints that much of the good news may already have been priced in before today’s selloff.
For bears, the combination of a stretched valuation narrative, post-earnings weakness and now a sharp daily decline with technical confirmation is notable. That said, Omnicom’s strong cash flow profile and diversified client base mean positive surprises remain possible, making disciplined stop placement important for anyone considering a short position.
3. Palo Alto Networks (PANW) – 13 technical sell signals
Price: $328.48 | Daily change: -9.28%
View the full technical analysis of Palo Alto Networks
Palo Alto Networks posted the steepest daily decline of any name on today’s list, falling more than 9% to $328.48. The magnitude of the move is particularly striking given that the stock surged approximately 13% just days earlier on 15 September, driven by AI-related cybersecurity optimism and a wave of upward analyst price-target revisions. That kind of sharp reversal following a big gap higher is itself a technical warning sign, often reflecting a failed breakout or profit-taking by short-term traders who bought the initial spike.
The underlying business story remains compelling: Palo Alto reported revenues and earnings ahead of consensus expectations, and the long-term demand thesis for enterprise cybersecurity — particularly as AI increases the attack surface for organisations — is broadly intact. However, forward guidance pointed to a moderation in growth rates, which tempered enthusiasm following the earnings release earlier in the month.
The combination of 13 bearish signals, a 9%-plus single-session decline and the context of a potential failed breakout gives short sellers a technically coherent narrative. Equally, PANW is a high-conviction long for many institutional investors, meaning any renewed AI-security catalyst could produce a rapid recovery. This is a name where position sizing and defined risk are especially important.
4. Autodesk (ADSK) – 12 technical sell signals
Price: $241.73 | Daily change: -2.41%
View the full technical analysis of Autodesk
Autodesk enters the list with 12 bearish technical signals and only 3 bullish readings, a ratio that points to broadly deteriorating momentum for the 3D design and engineering software group. The stock fell 2.41% on 18 September, extending a pattern of choppy price action that has characterised much of the year. Autodesk’s share price appeared to rebound in mid-September after investors reassessed a raised full-year outlook, but technical overhead resistance has repeatedly capped recovery attempts.
The fundamental backdrop has been mixed. Late August brought a guidance miss at the adjusted earnings midpoint that sent the stock down nearly 4% in a single session. The company’s acquisition of MaintainX added integration costs that weighed on near-term profitability, and conservative forward profit guidance has done little to rebuild confidence among growth-oriented investors. On the positive side, Autodesk’s cash flow profile has attracted favourable commentary, and the stock has shown an ability to bounce from key support levels.
From a technical perspective, the stock faces a ceiling that has repelled three separate rallies, while current support sits only around 5% below recent levels — a narrow trading range that could resolve in either direction. Bears will watch closely for any break below near-term support, while noting the significant risk of a snapback if sentiment shifts.
5. Constellation Brands (STZ) – 12 technical sell signals
Price: $129.35 | Daily change: -0.98%
View the full technical analysis of Constellation Brands
Constellation Brands rounds out the list with 12 bearish technical signals and 6 bullish ones — the most balanced bear-to-bull ratio among today’s candidates, which warrants extra caution for anyone considering a short. The maker of Modelo and Corona beer has seen its shares slide meaningfully over recent months, with a roughly 3.8% decline in the weeks following the last earnings report and a further 3.9% drop tied to a conference appearance that revived concerns about consumer demand trends in its core beer segment.
Management has moved to address structural issues, including a supply-chain leadership appointment and a strategy refinement across its beer portfolio focusing on brand-specific growth playbooks and consumer occasion targeting. The company also reaffirmed its full-year outlook, which should provide some fundamental floor. Nevertheless, the demand-concern narrative appears to be gaining traction with investors, and the stock has underperformed the broader index over the relevant period.
The relatively moderate daily decline of under 1% on 18 September, combined with 6 bullish signals still present in the scanner, suggests the bearish case here is less clear-cut than for names higher up this list. Potential short sellers should be mindful that a valuation re-rating or a stronger-than-expected earnings print could swiftly reverse the technical breakdown. Careful risk management and clear stop-loss levels are advisable.
Disclaimer: This article is produced for informational and educational purposes only and does not constitute investment advice or a solicitation to buy or sell any security. Technical analysis identifies patterns in historical price and volume data; it does not guarantee future results. Short selling carries substantial risks, including theoretically unlimited losses, and is not suitable for all investors. Always conduct your own due diligence and consult a qualified financial adviser before making any investment decision. The Wall Street Stock Investors Club and its contributors may or may not hold positions in any of the securities mentioned.