Déjà Vu Is Back: Fading Momentum, Massive Systematic Longs, Serious Downside Convexity

Momentum loss?

SPX has gone essentially nowhere since October, despite the broadly bullish tone. The déjà-vu we’ve flagged recently continues to build. From the autumn 2023 lows to early 2025, SPX rallied roughly 37%, then spent Oct 2024–Feb 2025 consolidating as momentum faded.

Today, the setup looks uncomfortably similar: the index is up around 39% from the Liberation Day lows, yet SPX has again done little since October. Momentum isn’t great, and the market is starting to feel tired beneath the surface.