5 Top-Ranked Growth Stocks to Strengthen Your Portfolio in September

Zacks highlighted Comfort Systems, Quanta Services, Seagate, Sandisk and Semtech as September growth-stock buys, with all carrying a Zacks Rank #1 and Growth Score of A. The recommendations are underpinned by AI-related demand: FIX's backlog reached $14.06B, up 73.2% year over year, while PWR's record backlog hit $53.4B, up 49%. Earnings estimates have risen across the group, led by Semtech (+30.8% in 30 days), Seagate (+28.7% in 60 days) and Quanta (+15.5% in 60 days), alongside projected current-year earnings growth exceeding 100% for Seagate, Sandisk and Semtech.

Analysis

The investable signal is not broad AI beta; it is the physical bottlenecks created after GPUs are purchased. PWR and FIX monetize utility interconnection, power-delivery and thermal-management constraints that can delay a data-center commissioning schedule by quarters. That makes their revenue less sensitive to a single hyperscaler capex pause than NVDA, but exposes both to labor availability, project execution and fixed-price contract risk; PWR is the cleaner multi-year power-grid expression, while FIX has the greater operating leverage to a cooling mix upgrade.

Storage and connectivity are later-cycle beneficiaries, but their earnings quality differs materially. STX and SNDK remain exposed to memory/storage pricing cycles and customer inventory digestion, so consensus upgrades can reverse quickly if hyperscalers shift procurement timing; SNDK also has NAND supply-discipline risk from industry capacity additions. SMTC has the most direct incremental content story at the networking-speed transition, but its revenue concentration and qualification dependence make the next two quarterly guides more important than the promotional growth narrative.

Near term, this screen is likely crowded after rapid estimate revisions, making a September chase unattractive absent a pullback or another capex confirmation from MSFT, AMZN, GOOG, META or ORCL. Over 1-3 months, utility load forecasts, hyperscaler capex guidance and 1.6T optical order commentary are the catalysts. Over 6-18 months, the key contrarian point is that grid and cooling shortages can shift spending from compute hardware toward construction and power infrastructure, extending PWR/FIX demand even if accelerator unit growth decelerates; the thesis fails if large campus projects are deferred, backlog conversion weakens, or margins are pressured by labor and equipment inflation.

Key Decisions for Investors

• Accumulate PWR on a 8-12% pullback or following confirmed utility-load/capex guidance; target a 6-12 month long versus short XLU or equal-dollar short a broad utility basket. The pair isolates accelerating transmission and interconnection spend from regulated-utility rate sensitivity; exit if book-to-bill falls below 1x for two quarters or Electric Infrastructure margins compress materially.
• Prefer long FIX / short FLR for a 6-9 month relative-value trade, sized modestly. FIX should retain better pricing power where specialized cooling and modular buildouts matter, while FLR has more commodity EPC and project-risk exposure; invalidate on evidence that data-center mechanical backlog is not converting to higher mix or if FIX's labor-cost growth outpaces revenue.
• Treat SMTC as an event-driven long only ahead of evidence of sustained 1.6T order conversion, not as a blanket AI position. Use a defined-risk call spread 3-6 months out after a post-earnings consolidation; upside depends on guidance durability, while a miss in data-center revenue or a customer qualification delay can produce a sharp multiple reset.
• Avoid initiating fresh directional longs in STX or SNDK solely on estimate momentum. Set alerts for enterprise SSD/HDD pricing, hyperscaler storage procurement, and NAND industry utilization; a long SNDK versus short STX becomes attractive only if flash pricing remains firm while HDD nearline demand softens, whereas broad storage demand weakness argues for no trade.
• Use MSFT, AMZN, GOOG, META and ORCL earnings as the gating catalyst for the entire basket: sustained capex growth with explicit power-constrained deployment commentary supports adding PWR/FIX; any coordinated capex moderation or data-center completion delays should trigger profit-taking first in SMTC, STX and SNDK, where inventory and qualification risk amplify downside.