High Short Interest Meets Growing Cash Pile as Sellas Nears REGAL Data Readout

Short interest hits 30.7% (7-year high), but Sellas has $114M cash and Phase 3 REGAL data imminent. The May 11 earnings report and shareholder vote on dilution will test the stock's 84% YTD surge.

The battle lines around Sellas Life Sciences are sharply drawn. Bearish bets have climbed to levels not seen in more than seven years, with 30.7% of the free float now sold short – the highest since January 2018. Yet the company has quietly bolstered its financial runway, giving it breathing room to see its most critical clinical catalyst through to completion.

That catalyst is the final analysis of the Phase 3 REGAL study, testing the cancer immunotherapy candidate Galinpepimut-S (GPS) in acute myeloid leukemia (AML). The trial is waiting for 80 pooled survival events before triggering the definitive readout. At the end of December 2025, 72 events had been recorded, meaning the trigger is now within reach. Each fresh announcement about event accrual brings the moment closer.

Against this tense backdrop, Sellas has shored up its balance sheet. The company ended fiscal 2025 with $71.8 million in cash, and during the first quarter of 2026 it added another $42.6 million from the exercise of warrants. That influx gives it a war chest to fund ongoing programs without resorting to dilutive equity raises – at least for now. For the first quarter, analysts expect a net loss of $0.06 per share, a modest miss from the $0.05 loss in the prior quarter when Sellas narrowly beat expectations.

Not all the news from the shareholder meeting will be comforting. Sellas has asked investors to approve an increase in its 2023 Amended and Restated Equity Incentive Plan by 20 million shares. The timing is no accident: by mid-April, fewer than 8,000 shares remained available for future grants. While such moves are standard for biotechs needing to retain talent, they also stoke dilution fears among existing holders. The proposal is a double-edged sword – necessary for employee retention but a red flag for those watching their stake.

Beyond REGAL, the pipeline includes SLS009, a Phase 2 candidate for newly diagnosed AML patients. That trial is recruiting using AI-driven precision models and biomarkers to identify individuals unlikely to respond to standard Venetoclax-based regimens. Progress there adds a second potential catalyst, though REGAL remains the dominant driver of sentiment.

Analyst opinion on the stock is split. Weiss Ratings reiterated a "Sell" recommendation in April. But other firms see material upside: the average price target stands at roughly €9, nearly double the current level of €4.53. The shares gained 7.1% on Monday, putting them about 13% below the 52-week high of €5.21. Year to date, the stock has surged roughly 84% based on U.S. listings. The relative strength index of 65.7 suggests a neutral to slightly overbought reading, while annualized volatility hovers near 79%.

The next real test comes on May 11, 2026, when first-quarter results are due. Investors will scrutinise both the study progress and the cash balance. The REGAL data will ultimately decide whether the high short interest reflects savvy risk assessment or a mispriced opportunity. Until then, every tick closer to the 80-event threshold builds pressure on both sides of the trade.