What is the sentiment among institutional investors and are there any notable pre‑IPO allocations that could influence post‑IPO support?

Institutional sentiment:

The “Sentiment: 70” rating in the release translates to a strongly positive bias among the investment community, especially among institutions that typically sit in the middle‑to‑upper end of the sentiment scale. The fact that the underwriters fully exercised their 2.5 million‑share option—an extra 11 % of the IPO size—signals that they received robust demand from their syndicate of institutional investors. In practice, underwriters only exercise the option when they are confident they can place the additional shares without depressing the price, which points to a solid institutional order book and a willingness to hold the stock for the medium term rather than flip it immediately.

Pre‑IPO allocations that could drive post‑IPO support:

All 19.2 million shares were sold directly by Heartflow, with no secondary‑seller float. The full‑exercise of the underwriters’ option means that a sizable block (2.5 M shares) was allocated to the underwriters’ institutional clients ahead of the pricing. Those investors—typically large asset managers, hedge funds, and strategic corporate owners—are likely to receive a “green‑shoe” allocation that they will be motivated to support in the aftermarket, especially given the company’s AI‑driven CAD platform and the premium $19 price that reflects a growth‑oriented valuation. Consequently, we can expect steady buying pressure in the first few weeks as these pre‑IPO holders look to protect their initial stake and the underwriters aim to avoid a post‑IPO price dip.

Trading implication:

With institutional demand already baked into the IPO and a positive sentiment backdrop, the stock should see relatively low volatility in the early trading days, provided the broader market remains stable. Traders can look for initial consolidation around the $19‑$20 range before testing higher levels on breakout volume. A breach above $20 with strong volume would likely be fueled by the same institutional groups adding to their positions, while a dip below $18 could trigger short‑covering and a rebound as underwriters and large investors step in to defend their allocations. In short, the institutional‑backed upside is the more compelling scenario, and positioning long on modest pull‑backs with a view to capture a breakout would be the prudent approach.