September's Small-Cap IPO Window, Read From the Prospectuses: Two Biotechs Upsized and Priced at the Midpoint or the Top, the One Insurer Priced at $12 Against a $15-to-$17 Range, and Four Blank-Check Sponsors Raised $750 Million Alongside

by Daniel Brenner · September 30, 2026

Senior Markets Analyst, The SmallCap Signal

Three operating companies completed U.S. initial public offerings between Sept. 17 and Sept. 28, and the final prospectuses they filed with the SEC tell a cleaner story about the small-cap IPO window than any market commentary: buyers paid up for late-stage biotech and pushed back on a founder-controlled specialty insurer. Alongside them, four blank-check companies filed final prospectuses for $750 million of units, our arithmetic from the four cover pages, which is a reminder that the SPAC pipe remains open at the same time.

Electra Therapeutics Inc. (Nasdaq: ETRA) went first. Its final prospectus, dated Sept. 17 and filed Sept. 18, shows 23,333,334 shares sold at $15.00 for gross proceeds of $350,000,010, with underwriting discounts of $1.05 a share and net proceeds to the company estimated at approximately $319.9 million, or $368.7 million if the 3,500,000-share option is exercised. The S-1/A filed Sept. 14 had marketed 21,666,667 shares at $14.00 to $16.00. The company therefore priced at the midpoint and sold about 1.67 million more shares than it set out to, our arithmetic from the two filings. Jefferies, TD Cowen, Evercore ISI and Cantor ran the books, and the offering closed Sept. 21 according to the company's 8-K.

Electra describes itself as a late clinical-stage biopharmaceutical company developing precision medicines for immune-mediated diseases and cancer that target signal regulatory proteins, or SIRP, with a lead antibody, ipsoprubart, formerly known as ELA026, that it is developing first for secondary hemophagocytic lymphohistiocytosis. The prospectus says the proceeds plus existing cash should fund operations into 2029, and in the same breath that this will not be enough to take any product candidate through approval and commercialization.

ADARx Pharmaceuticals Inc. (Nasdaq: ADRX) closed the window with the largest deal of the three. The final prospectus, dated Sept. 24 and filed Sept. 28, shows 26,250,000 shares at $17.00 for gross proceeds of $446,250,000, with a 3,937,500-share option. The S-1/A filed a week earlier, Sept. 21, marketed 21,875,000 shares at $15.00 to $17.00 and estimated net proceeds from the IPO and the concurrent private placement of approximately $397.1 million assuming a $16.00 midpoint. The final document estimates net proceeds from the IPO and a concurrent private placement at approximately $495.3 million, or $557.5 million with the option. So ADARx priced at the top of its range and increased the share count by 4,375,000, our arithmetic.

The private placement is the detail worth reading. Under a purchase agreement dated Sept. 13, AbbVie Inc. agreed to buy enough stock at the IPO price to own approximately 4.9% of ADARx after closing, capped at $100.0 million, and the Sept. 28 8-K says that at $17.00 that came to 5,255,542 shares, placed through J.P. Morgan, Morgan Stanley, TD Securities, UBS and LifeSci Capital for a 2.0% placement fee. The offering and the placement closed together on Sept. 28. ADARx is a late-clinical stage siRNA company; its lead program, agazisiran, is in three Phase 2 trials in complement-mediated kidney diseases, PNH and geographic atrophy, and the prospectus says the money should last into 2030.

Orion180 Insurance Group Inc. (Nasdaq: OIG) carries the same Sept. 17 prospectus date as Electra and went the other way on price. The S-1/A filed Sept. 9 marketed 20,000,000 Class A shares at $15.00 to $17.00 and estimated net proceeds of approximately $296 million. The final prospectus, dated Sept. 17, shows the same 20,000,000 shares at $12.00, gross proceeds of $240,000,000, underwriting discounts of $0.78 a share, and estimated net proceeds of approximately $220 million, or $253 million if the 3,000,000-share option is exercised. RBC Capital Markets and UBS were the joint book-running managers and representatives of the underwriters, with Raymond James alongside them on the top line of the cover and Goldman Sachs, Deutsche Bank, Citizens Capital Markets and Texas Capital Securities beneath; shares were to be delivered on or about Sept. 21.

Orion180 calls itself the second-largest excess-and-surplus homeowners insurer in the United States by direct written premiums, operating in 14 states with approximately $601 million of managed premiums written in the twelve months to June 30, 2026, according to the prospectus. Founder and chief executive Kenneth Gregg holds all of the ten-vote Class B stock and will control 93.9% of the voting power after the offering, making the company a "controlled company" under Nasdaq rules. The use-of-proceeds section says the company may repay part of the $282 million outstanding under its new credit facility, which the risk factors say was used in part to fund dividends paid in May and September, and the underwriting section discloses that affiliates of RBC, UBS and Raymond James, all underwriters, would each receive 5% or more of the net proceeds through that repayment, which is why the deal was made under FINRA Rule 5121, the conflict-of-interest rule, with Goldman Sachs acting as qualified independent underwriter.

Three data points do not make a market, but the pattern is legible. The two deals that grew in size and priced at or above the midpoint were pre-revenue biotechs with named lead assets, defined Phase 2 or Phase 3 spending plans, multi-year runway statements and, in ADARx's case, a strategic buyer writing a check at the IPO price. The deal that was cut was a self-described "high growth, high-margin" founder-controlled insurer writing homeowners cover in the excess-and-surplus market, carrying $282 million of credit-facility debt and coming to market with underwriters whose affiliates stood to be repaid from the proceeds. The pricing suggests investors weighed the governance and the balance sheet at least as heavily as the growth claim.

The cost of the cut is visible in the filings rather than the tape. Orion180's estimated net proceeds fell from approximately $296 million to approximately $220 million between the Sept. 9 amendment and the Sept. 17 prospectus, our comparison of the two documents, without any change in the number of shares sold. Because the company kept the share count and cut the price, the dilution to Mr. Gregg is the same as it would have been at $16; what shrank is the capital that arrives to grow the book and pay down the credit facility.

The blank-check flow ran in parallel. Haymaker Acquisition Corp V filed a final prospectus Sept. 18 for 25,000,000 units at $10.00, or $250,000,000, each unit one Class A share and one-third of a warrant, with the full $250 million to be held in trust at Continental Stock Transfer & Trust. Live Oak Acquisition Corp. VI followed on Sept. 23 with 20,000,000 units for $200,000,000, and Leader's Advantage Acquisition Corp. (Sept. 21) and Bluerock Acquisition Corp. II (Sept. 25) each filed for 15,000,000 units, $150,000,000 apiece. All four are Cayman Islands exempted companies with no target selected, according to their cover pages. The Roman numerals in three of the four names tell their own story about serial sponsors.

Put the two piles side by side. The three operating-company IPOs raised $1,036.25 million gross before options and before the AbbVie placement, our arithmetic from the three cover tables, against $750 million for the four SPACs. On those figures, our arithmetic again, roughly forty cents of every dollar raised across these seven deals went into trust accounts looking for a deal rather than into a business.

What the filings do not tell us is how any of the three trades. This piece deliberately cites no aftermarket prices; the closes since listing belong in a movers column with documented 9/29 levels. Nor do the prospectuses say whether the over-allotment options were exercised, which, on the option share counts stated and by our arithmetic, would take gross proceeds for Electra to about $402.5 million and for ADARx to about $513.2 million; that will show up in the closing 8-Ks or the first 10-Qs.

Two things to watch. First, whether the biotech bid holds for the next names in the queue: both ADARx and Electra are Nasdaq Global Select listings, and TD Cowen appears on both covers. Second, whether Orion180's discount was specific to Orion180 or a verdict on E&S homeowners insurance as a public-market product heading into the tail of hurricane season. The first quarterly report from each will be the first time the prospectus numbers meet audited actuals.