Shell plc (NYSE:SHEL) shares are trading lower during Wednesday’s session, even after the company reported a portfolio move tied to its Gulf of America platform interests. Shell has agreed to sell its 50% non-operated stake in the Na Kika platform and related Gulf of America fields, along with its wholly owned Coulomb tieback.The assets will be sold to subsidiaries of Talos Energy, Inc. (NYSE:TALO) and Ridgewood Energy Corporation for $1.7 billion, subject to customary adjustments and contingent payments.What Is Shell’s Gulf of America Asset Sale Catalyst?Shell says the sale fits the company’s ongoing portfolio management approach of pruning assets and recycling capital. Shell plc expects the sale to close by the end of 2026, with an effective date of July 1, 2025, subject to regulatory approvals. As part of the agreement, Shell will receive uncapped upside-linked payments through 2027, overriding royalty interests on future Na Kika tiebacks, and transfer certain decommissioning obligations to the buyers.BP p.l.c., which operates Na Kika and owns the remaining 50% interest, has a 30-day preferential right to purchase Shell’s stake. Notably, the assets produced 37,000 barrels of oil equivalent per day on a Shell entitlement basis in 2025, although the company does not expect them to be significant contributors to production by 2030. Shell will also retain offtake rights under commercial agreements.Shell Stock: Critical Levels To WatchFrom a trend perspective, Shell is in a pullback, trading 7% below its 20-day SMA ($82.23), 10% below its 50-day SMA ($85.01), and 10.8% below its 100-day SMA ($85.74). It’s also about 4% below the 200-day SMA ($79.65), which puts the longer-term trend line in play as a "make-or-break" area for bulls.MACD is the cleaner momentum lens right now: it’s below its signal line with a negative histogram, which typically means upside pressure is fading unless buyers can force a reversal. RSI has also shown extremes this year—overbought in April and oversold in June—which reinforces the idea that the stock has been swinging rather than trending smoothly.