Short Report: Vera Therapeutics bears retreat as stock rallies

Welcome to this week’s installment of “The Short Interest Report” – The Fly’s weekly recap of short interest trends among some of the most widely followed high-short-float stocks. Using the data from our partner Ortex.com, which utilizes the latest information from stock lenders to estimate short interest changes for thousands of publicly traded companies, this report will screen for some of biggest changes in short interest as a percentage of free float and days-to-cover ratios while also considering the short interest data on some of the more volatile and heavier-traded names of the week. Based on the availability of data from Ortex, the report tracks the trading period that covers prior Friday through Thursday of this week, excluding holidays. As a basis of comparison for stocks discussed below, the S&P 500 index was down 1.8%, the Nasdaq Composite was down 2.5%, the Russell 2000 index was down 3.2%, the Russell 2000 Growth ETF (IWO) was down 4.4%, and the Russell 2000 Value ETF (IWN) was down 2.7% in the five-day trading session range through December 18.

SHORT INTEREST GAINERS

• Ortex-reported short interest on Mobileye Global (MBLY) had receded to 15-month lows below 15% beyond the first week of November, though bearish appetite has since picked up as the selling pressure on the stock resurfaced. This week, shorts as percentage of free float on Mobileye Global rose from 15.1% to 21.9%, matching the highs seen five weeks ago, while days-to-cover declined from 1.4 to 1.3 as trading volumes were relatively elevated this month. Mobileye shares fell 12% toward the $10 level, the lowest since last September, and the stock has now shed 50% from its July highs – a similar rate of decline year-to-date.
• Ortex-reported short interest on Neurogene (NGNE) troughed at seven-month low of 47% on November 14 as shares sold off 14% that day in the wake of the company’s Q3 results and as bears booked profits. Shorts as a percentage of free float has since ticked higher, with this week registering an increase of eight percentage points to 63.1% – a four-month high. The stock was down 9.3% in the five-day period covered through Thursday and has now lost 45% from its 2025 highs in mid-October, though year-to-date, Neurogene is still down 10%.

SHORT INTEREST DECLINERS

• Ortex-reported short interest on Vera Therapeutics (VERA) reached a ten-month high of 24.5% late last week, though with the stock price run-up unrelenting, bears are conceding their losses. This week, shorts as a percentage of free float on the name slipped from 24.6% to 21.2% even as days-to-cover on the name rose from 2.7 to 3.3. Meanwhile, the stock traded up 3.6% in the five-day period through Thursday, and shares have now gained 74% in a period of about four weeks. The stock has received multiple price target hikes from sell-side analysts in December, reflecting the positive competitive FDA updates for Otsuka Pharmaceutical’s Voyxact in IgA Nephropathy, with research suggesting that Vera would have a pricing advantage when and if its own treatment in the indication does well in clinical trials and is ultimately approved by regulators.
• Ortex-reported short interest on Madrigal Pharmaceuticals (MDGL) has been on retreat from its 38% multi-month peak in mid-October, though this week has seen a particularly pronounced pullback in bearish expression. Short positioning as a percentage of free float was down from 32.7% to 29% in the five-day period covered – the lowest level since May of 2024 – while days-to-cover slipped from 4.5 to 3.7, also the low for 2025. The stock was down 4.7% this week through Thursday, though shares spiked nearly 9% on Friday in conjunction with a bullish note from Piper Sandler which raised its price target from $540 all the way to $900 – the highest among analysts covering the name. Madrigal shares are now also up 92% year-to-date.