What grey market premium is, and what it is not

The grey market is an informal, over-the-counter market in IPO applications and in shares before they list. It has no exchange, no clearing house, no regulator and no obligation on anyone to settle. The "premium" is what dealers in that market are quoting over the issue price.

Quotes are collected by intermediaries and relayed by websites. They differ between sources, they are not audited, and nobody is required to publish a trade that happened at that price — or any trade at all.

Because it is genuinely informative about current enthusiasm, and because pretending it does not exist would not make anyone better informed. A premium that halves overnight is telling you something real about sentiment, even if it tells you nothing reliable about listing day.

So it appears on every issue page, labelled unofficial on every surface, and it is capped at 8 of the 100 points in the IPOVista score — enough to tilt a score, never enough to carry one.

Almost every IPO site publishes grey-market premium. Very few ever go back and check it. The home page carries a chart that does: every tracked listing's last pre-listing quote plotted against the move the stock actually made, with the identity line where the two would be equal.

Across the listings in this dataset the premium has called the direction well and the magnitude badly, missing by about ten percentage points on average and tending to undershoot. That is a small sample from one dataset and should not be generalised — but it is a number, which is more than the usual treatment offers.