S&P 500's Best Week Since November: Which Cross-Sector Stocks Drove the Rally and Who Got Left Behind?
The S&P 500 notched its best weekly performance since November 2025 as of April 10, 2026, with the SPY ETF climbing 2.56% in the week ending April 5 alone amid broad market optimism. This cross-sector rally—fueled by easing macro fears, AI hype, and energy sector rebounds—highlighted stark divergences: tech and energy leaders soared while consumer and select software names cratered. Which stocks positioned investors for outsized gains, and who faces headwinds despite the tide?
What changed? After months of choppy trading tied to inflation data and Fed signals, recent weeks saw a rotation beyond mega-caps. AI infrastructure demand propelled semis and cloud plays, oil refining margins rebounded on crude stability, and defensive sectors lagged as risk appetite returned. With the index up ~2.6% weekly, top performers gained double-digits in days—signaling potential trend starters.
Nebius Group (NBIS): AI Cloud Rocket Fuels 37% Surge
Nebius Group N.V., formerly Yandex, builds full-stack AI infrastructure including GPU clusters and cloud platforms via its Nebius unit, alongside data labeling (Toloka AI) and autonomous tech (Avride). In this rally, NBIS exploded +36.8% over five days and +33.2% monthly, outpacing the S&P as AI buildouts accelerate.
The theme hits directly: hyperscalers' GPU hunger boosts Nebius' workloads, with TTM revenue growth exploding 411% on AI tailwinds.
| Metric | Value |
|---|---|
| Market Cap | $34.8B |
| Price (Current) | $144.89 |
| P/E TTM | 284x |
| PS TTM | 65x |
| Revenue Growth TTM | +411% |
| 5-Day Return | +36.8% |
| YTD Return | +44.4% |
Q4 2025 earnings aren't detailed here, but explosive growth underscores AI moat. Verdict: Strong buy—top exposure to AI infra at frothy but justified multiples.
Micron Technology (MU): Memory Boom Powers 13% Jump
Micron designs DRAM, NAND, and storage for AI data centers, mobiles, and autos. Its +13.5% five-day gain (YTD +40%) rode HBM demand, with fiscal Q1 2026 revenue hitting records amid 86% TTM sales growth.
AI servers' memory needs supercharge MU: HBM TAM seen at $100B by 2028 (40% CAGR). Recent quarters show Q4 FY2025 revenue strength, EPS records.
| Metric | Value |
|---|---|
| Market Cap | $474B |
| Price (Current) | $420.59 |
| P/E TTM | 19.6x |
| PS TTM | 8.1x |
| Revenue Growth TTM | +86% |
| EBIT Margin TTM | 58% |
| 5-Day Return | +13.5% |
| 1-Month Return | +10.5% |
Earnings highlighted 1-gamma DRAM ramps and $20B FY2026 capex. Verdict: Bull—AI memory leader with attractive valuation.
Tower Semiconductor (TSEM): Analog Semi Tailwinds Lift 20%
Tower fabs analog/mixed-signal chips for auto, industrial, and RF. Up 19.9% in five days (+8.4% monthly), TSEM benefits from silicon photonics and power management demand.
Rally ties to semi rotation: Q4 2025 revenue $440M (+14% YoY), full-year $1.57B (+9%), with 5x capacity expansion planned.
| Metric | Value |
|---|---|
| Market Cap | $22.8B |
| Price (Current) | $203.59 |
| P/E TTM | 103x |
| PS TTM | 14.5x |
| Revenue Growth TTM | +9% |
| 5-Day Return | +19.9% |
| YTD Return | +13.7% |
Q1 2026 guide: $412M revenue (+15% YoY start). Verdict: Buy—niche growth in photonics undervalued.
Valero Energy (VLO): Refining Rebound Adds 7.7%
Valero refines fuels and produces ethanol/renewables. +7.7% five-day gain (YTD +40.7%) reflects margin recovery, throughput records.
Energy rotation in rally: TTM revenue dip -4.5%, but Q4 2025 strong on ops.
| Metric | Value |
|---|---|
| Market Cap | $71.4B |
| Price (Current) | $238.82 |
| P/E TTM | 31x |
| PS TTM | 0.6x |
| Revenue Growth TTM | -4.5% |
| 5-Day Return | +7.7% |
| 1-Month Return | +17.9% |
2026 capex $1.7B, Q1 throughput steady. Verdict: Mild bull—cyclical play if oil stable.
Ulta Beauty (ULTA): Retail Weakness Drags -19%
Ulta retails beauty via 1,300+ stores and e-com. It plunged -19.5% five days (-26.9% monthly), YTD -16.7%, as consumer spending cools.
Rally bypassed retail: TTM revenue +9.7%, but margins squeezed.
| Metric | Value |
|---|---|
| Market Cap | $23.1B |
| Price (Current) | $520.38 |
| P/E TTM | 20x |
| PS TTM | 1.9x |
| Revenue Growth TTM | +9.7% |
| 5-Day Return | -19.5% |
| YTD Return | -16.7% |
Verdict: Bear—avoid amid discretionary pullback.
Fair Isaac (FICO): Software Selloff Hits -19%
FICO's analytics power credit scores and decisions. Down -19.4% five days (-14.1% monthly, YTD -29%), despite 16% TTM growth.
Rotation hurt high-flyers: Scores/software strong, Q1 FY2026 revenue $512M.
| Metric | Value |
|---|---|
| Market Cap | $21.9B |
| Price (Current) | $922.37 |
| P/E TTM | 34x |
| PS TTM | 10.6x |
| Revenue Growth TTM | +16% |
| EBIT Margin TTM | 83% |
| 5-Day Return | -19.4% |
Reiterated FY2026 guide amid macro uncertainty. Verdict: Bear—overextended post-rally.
Ranked Conviction: Plays for the Next Leg
- NBIS (Highest conviction buy): Pure AI infra play, explosive growth.2. MU: Balanced semi exposure, reasonable P/E.3. TSEM: Niche upside in photonics.4. VLO: Energy value if rally broadens.Avoid ULTA and FICO—laggards signal sector risks.
Risks & Monitors: Fed pivot delays could reverse rotation (watch 10Y yield >4.5%); AI hype fades if capex slows (track MU HBM orders); consumer data (Ulta comps). Next S&P rebalance or CPI print as catalysts.