SpaceX’s expected IPO, potentially targeting a nearly $2 trillion valuation, has boosted optimism around smaller space stocks.

RKLB has surged 83% so far this month, SIDU climbed 82%, ASTS gained 68% and BKSY advanced 54% amid the sector-wide rally.

Sidus Space has gained momentum through AI-focused satellite infrastructure, orbital data-storage partnerships, Earth-imaging systems and defense-related space tech.

Retail traders are crowding into Rocket Lab USA (RKLB) and AST SpaceMobile (ASTS) on mounting SpaceX IPO excitement, but one smaller space stock is quietly emerging as the sector’s cheapest high-upside play.

Retail Crowns RKLB, ASTS As Top Space Bets

A recent Stocktwits poll asking investors which space company they are most bullish on over the next five years showed Rocket Lab narrowly leading with 39% of votes, followed closely by AST SpaceMobile at 38%. Sidus Space (SIDU) received 16% support, while BlackSky Technology (BKSY) drew just 7%. The poll generated more than 3,100 votes.

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Excitement around space stocks accelerated after SpaceX moved closer to what could be the largest IPO in history, with the Elon Musk-led company reportedly seeking a valuation near $2 trillion. Investors see SpaceX as more than a rocket company, viewing it instead as a long-term orbital infrastructure and AI platform, spanning satellite broadband, launch systems and space transportation.

The expected listing has spurred interest across smaller space stocks seen as indirect beneficiaries of the broader SpaceX trade. Optimism grew further after FTSE Russell proposed faster index-entry rules for newly listed mega-cap IPOs, potentially opening the door for rapid benchmark inclusion and large passive-fund flows into SpaceX.

The rally has already been dramatic, with RKLB up 83% so far this month, narrowly ahead of Sidus Space at 82%, while AST SpaceMobile climbed 68% and BlackSky gained 54%.

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In overnight trading heading into Thursday, SIDU plunged 20% after the company priced a $100 million stock offering involving 19.7 million shares at $5.08 per share, priced at-the-market under Nasdaq rules. Sidus said the proceeds will be used for working capital and general corporate purposes, with the offering expected to close on May 29.

Meanwhile, ASTS fell 5%, RKLB slipped 4%, and BKSY edged down around 2%.

SIDU Quietly Emerges As Space Sector Underdog

Despite receiving far less retail attention than RKLB or ASTS, Sidus Space has quietly emerged as one of the sector’s strongest performers, with the stock also standing out as the only player among the four still showing analyst upside based on Koyfin consensus estimates, with an upside of about 64.5%, while AST SpaceMobile, Rocket Lab and BlackSky all currently imply downside from current levels.