IPO float scarcity is the reason a stock can rocket on day one without telling you anything about what it’s actually worth. On July 26 (ET), China’s largest DRAM maker, CXMT, debuted on Shanghai’s STAR Market and surged more than 470%, briefly making it China’s most valuable listed company — on an $8.6 billion IPO that had been oversubscribed hundreds of times over.
Here’s the mechanism. In China’s retail IPO system, you don’t pay when you apply — you get lottery entries based on shares you already hold, and only pay if you win. CXMT drew bids for shares worth roughly 200 times what was on offer from retail investors alone, and the final allotment rate was under 0.5%. That means almost everyone who wanted in couldn’t get shares at the IPO price. So on day one, anyone who still wants exposure has to buy in the open market — bidding against a huge pool of disappointed applicants for a genuinely small number of tradable shares.
That’s float scarcity: when demand vastly outstrips the shares actually available to trade, price gets set by whoever’s most desperate to get in, not by a broad market’s read on fair value. A 470% pop looks like a verdict. It’s closer to an auction among people who missed the first round.
This isn’t unique to CXMT. When SMIC listed on the same exchange in 2020, it pulled in such a disproportionate share of trading volume that it dragged the broader tech index down for days — the same scarcity dynamic, just distributed differently. The lesson holds for any oversubscribed listing: watch what happens once lockups expire and more shares actually become tradable. That’s usually when the price starts reflecting the business instead of the shortage.
For Korean investors, the more durable story here isn’t the debut pop — it’s that CXMT now has $8.6 billion to expand production, aimed squarely at the commodity DRAM market where Samsung and SK Hynix compete. That’s a supply question, not a one-day trading pattern.
My take: Scarcity felt like conviction, for one day.
Not advice. Just how I see it.