I'd be careful treating Rocket Lab or AST SpaceMobile as "SpaceX proxies".

The bull case is straightforward: a successful SpaceX IPO could bring massive attention and fresh capital into the space sector, lifting related names through sentiment alone. That's what many traders are betting on.

The bear case is that expectations may already be priced in. If investors can finally buy SpaceX directly, capital could rotate out of RKLB, ASTS, Virgin Galactic and Redwire rather than into them. History is full of "sell-the-news" events following highly anticipated listings.

Between the two, RKLB has a clearer business model today with launch services, spacecraft systems, and growing government contracts. ASTS offers larger potential upside if its direct-to-cell network succeeds, but execution risk remains much higher.

For me, the choice is not "long or short the sector". It is whether fundamentals justify the valuation after the IPO excitement fades. If I wanted exposure, I'd prefer gradually accumulating RKLB during periods of weakness rather than making an all-or-nothing bet on IPO hype. The biggest risk is assuming SpaceX's success automatically translates into gains for every space stock. Markets rarely make it that easy.