Key Highlights

  • LENZ Therapeutics has the highest days to cover at 18.9, with 37.74% of float sold short as of August 31, 2026.
  • C4 Therapeutics is trading 7.83% higher at $3.46 with 42,722,018 shares sold short at the October 15 settlement date.
  • Groupon shows 15.45 days to cover and reports third-quarter results on November 5, 2026.
  • Tripadvisor has 38,397,250 shares sold short, about 32.8% of shares outstanding (calculated).
  • Serve Robotics has 10.43 days to cover after an 11.36% jump on October 27.

Which Stocks Show the Highest Days to Cover in Short Interest on October 28?

Six stocks show days to cover above 10 in the short-interest readings available on Wednesday, October 28, 2026. LENZ Therapeutics (NASDAQ:LENZ) is trading 1.43% lower at $3.11 with 18.9 days to cover, C4 Therapeutics (NASDAQ:CCCC) is trading 7.83% higher at $3.46 with 16.95 days, and Groupon (NASDAQ:GRPN) is trading 2.72% lower at $16.07 with 15.45 days. Tripadvisor (NASDAQ:TRIP) is trading 1.89% lower at $8.81 with 13.24 days, Xponential Fitness (NYSE:XPOF) is trading 0.86% higher at $4.12 with about 12.4 days, and Serve Robotics (NASDAQ:SERV) is trading 1.87% lower at $2.88 with 10.43 days.

The order follows days to cover as stated for each stock. Bases differ: four readings are for the October 15 settlement date, LENZ Therapeutics' is for August 31 and Xponential Fitness' for September 30. Percentages are of float for LENZ Therapeutics and Xponential Fitness but of shares outstanding for the others, so they are not merged into one ranking.

LENZ Therapeutics: Why Is a Stock With 18.9 Days to Cover Drifting Lower?

LENZ is a commercial-stage eye-health company whose product VIZZ won FDA approval on July 31, 2025 for presbyopia. Shares are trading 1.43% lower at $3.11 with no dated company release, extending a slide from a $3.79 close on October 6 and $5.96 on September 4. The August 31, 2026 reading shows 10,874,649 shares sold short, down 2.86% from 11,195,137, equal to 37.74% of float. Second-quarter total revenue was $5.486 million, including net product sales of $1.736 million, against a net loss of $31.918 million. Cash plus marketable securities were $220.0 million at June 30, compared with a market capitalisation of $102.74 million at the October 16 close.

C4 Therapeutics: What Sits Behind the 7.83% Gain at 16.95 Days to Cover?

C4 is a clinical-stage biopharmaceutical company in Watertown, Massachusetts, whose main candidate, cemsidomide, targets multiple myeloma. Shares are trading 7.83% higher at $3.46, an implied prior close near $3.21 (calculated), and no announcement dated today accompanied the move. Short interest was 42,722,018 shares for the October 15 settlement date, up 2,326,353, or about 34.7% of shares outstanding, with no separate float figure published. Cash of $300.4 million at June 30 is expected to fund operations through the end of 2028, and the second-quarter net loss was $23.6 million, or $0.18 per share.

Groupon: Can 15.45 Days to Cover Meet a November 5 Earnings Report?

Groupon runs an online marketplace connecting consumers with local merchants. Shares are trading 2.72% lower at $16.07, an implied prior close of about $16.52 (calculated), and no release dated today accompanied the move. Short interest was 12,549,059 shares for the October 15 settlement date, up 494,805, or about 30.9% of shares outstanding (calculated), against average daily volume of 812,222 shares. Second-quarter global revenue and billings each fell 1%, and adjusted EBITDA was $14.8 million. Third-quarter guidance calls for revenue of $128 million to $130 million and billings growth of 4% to 6%.

Tripadvisor: Does 13.24 Days to Cover Weigh on a 1.89% Dip?

Tripadvisor operates the reviews platform and the Viator experiences marketplace. Shares are trading 1.89% lower at $8.81, an implied prior close of about $8.98 (calculated), with no release dated today. Short interest was 38,397,250 shares for the October 15 settlement date, about 32.8% of the 117.2 million shares outstanding (calculated), and days to cover rose to 13.24 from 8.65 two weeks earlier. Second-quarter revenue from continuing operations was $441.9 million, down 7%, with Experiences up 3% to $278.6 million. The $700 million sale of TheFork to American Express (NYSE:AXP) is expected to complete by year-end.

Xponential Fitness: What Do 12.4 Days to Cover Mean Beside a Rights Plan and Strategic Review?

Xponential franchises boutique fitness studios under five brands, including Club Pilates. Shares are trading 0.86% higher at $4.12, an implied prior close of about $4.08, with no dated release today. Short interest was 10,912,823 shares for the September 30 settlement date, 29.14% of float, about 5.8% above the September 15 reading. The board adopted a limited-duration rights plan on October 12 with a 19.9% trigger, expiring October 11, 2027, while a strategic alternatives review continues and may not result in a transaction. Second-quarter revenue was $66.0 million, down 13%, and guidance for adjusted EBITDA was cut on August 6 to $91 million to $97 million.

Serve Robotics: How Do 10.43 Days to Cover Frame the Pullback After Tuesday's 11.36% Jump?

Serve designs and operates autonomous sidewalk delivery robots and was spun out of Uber (NYSE:UBER) in 2021. Shares are trading 1.87% lower at $2.88, an implied prior close of about $2.94 (calculated), after an 11.36% rise on Tuesday, October 27; no release dated today accompanies the dip. Short interest was 31,217,126 shares for the October 15 settlement date, about 36% of shares outstanding (calculated, a share-count basis rather than float). The company cut 2026 revenue guidance to $9 million to $10 million from $26 million after weaker Uber Eats volumes, while revenue from DoorDash (NASDAQ:DASH) rose nearly 50% sequentially.

Days to Cover Compared: How Far Apart Are the Most Shorted Names?

LENZ Therapeutics' 18.9 days is 8.47 days above Serve Robotics' 10.43, C4 Therapeutics' 16.95 is 1.50 days above Groupon's 15.45, and Groupon is 2.21 days above Tripadvisor's 13.24 (all calculated). C4 Therapeutics' 7.83% gain is 9.26 percentage points above LENZ Therapeutics' 1.43% decline and 10.55 points above Groupon's 2.72% decline (calculated).

Among the October 15 readings, C4 Therapeutics has 42,722,018 shares sold short, 4,324,768 more than Tripadvisor's 38,397,250, which is 7,180,124 more than Serve Robotics' 31,217,126 (calculated). The ranking changes with the measure: on percent of shares outstanding Serve Robotics is highest at about 36% (calculated), then C4 Therapeutics at 34.7%, Tripadvisor at 32.8% and Groupon at 30.9% (calculated), although Serve Robotics is last on days to cover.

What to Watch Next: November 5 Reports From Groupon, Tripadvisor and Xponential Fitness and the November 10 Short-Interest Release

Groupon, Tripadvisor and Xponential Fitness are all scheduled to report third-quarter results on Thursday, November 5, 2026. Updated short-interest data for the October 30 settlement date are expected on November 10, covering C4 Therapeutics, Groupon, Tripadvisor and Serve Robotics. Serve Robotics announced on October 22 that it will report third-quarter results, and LENZ Therapeutics' next results will show whether VIZZ sales are growing against the $1.736 million second-quarter figure. C4 Therapeutics targets an elranatamab dose-escalation update in the second half of 2026, and the TheFork closing is expected before December 31.