Short Interest in Rallybio Corporation (NASDAQ:RLYB) Decreases By 63.2%

30 May 2026, 09:38 by Amy Steele · The Cerbat Gem

Rallybio Corporation (NASDAQ:RLYB – Get Free Report) was the target of a large decrease in short interest during the month of May. As of May 15th, there was short interest totaling 578,792 shares, a decrease of 63.2% from the April 30th total of 1,572,902 shares. Based on an average daily volume of 1,001,411 shares, the short-interest ratio is currently 0.6 days. Currently, 12.2% of the shares of the stock are short sold.

Insider Buying and Selling at Rallybio

In other news, major shareholder Adar1 Capital Management, Llc bought 120,804 shares of Rallybio stock in a transaction dated Monday, May 4th. The shares were purchased at an average cost of $13.97 per share, with a total value of $1,687,631.88. Following the completion of the acquisition, the insider owned 744,683 shares of the company’s stock, valued at $10,403,221.51. This trade represents a 19.36% increase in their position. The transaction was disclosed in a legal filing with the Securities & Exchange Commission, which is available through the SEC website. Insiders bought a total of 302,473 shares of company stock worth $4,229,715 in the last ninety days. Company insiders own 10.30% of the company’s stock.

Institutional Investors Weigh In On Rallybio

A number of large investors have recently modified their holdings of the business. Citadel Advisors LLC boosted its position in shares of Rallybio by 576.1% during the 3rd quarter. Citadel Advisors LLC now owns 438,705 shares of the company’s stock valued at $219,000 after acquiring an additional 373,821 shares during the last quarter. Renaissance Technologies LLC raised its position in shares of Rallybio by 16.9% during the 4th quarter. Renaissance Technologies LLC now owns 835,692 shares of the company’s stock valued at $573,000 after buying an additional 120,892 shares during the period. Susquehanna International Group LLP raised its position in shares of Rallybio by 485.9% during the 3rd quarter. Susquehanna International Group LLP now owns 136,294 shares of the company’s stock valued at $68,000 after buying an additional 113,031 shares during the period. XTX Topco Ltd lifted its holdings in Rallybio by 64.6% in the fourth quarter. XTX Topco Ltd now owns 97,313 shares of the company’s stock valued at $67,000 after acquiring an additional 38,205 shares during the last quarter. Finally, Geode Capital Management LLC lifted its holdings in Rallybio by 1.2% in the fourth quarter. Geode Capital Management LLC now owns 248,005 shares of the company’s stock valued at $170,000 after acquiring an additional 2,996 shares during the last quarter. Hedge funds and other institutional investors own 90.34% of the company’s stock.

Wall Street Analyst Weigh In

RLYB has been the subject of several research analyst reports. Wall Street Zen upgraded Rallybio to a “hold” rating in a report on Saturday, March 28th. Weiss Ratings reaffirmed a “sell (d-)” rating on shares of Rallybio in a report on Friday, May 8th. One research analyst has rated the stock with a Sell rating, According to MarketBeat.com, Rallybio presently has a consensus rating of “Sell”.

Read Our Latest Stock Analysis on RLYB

Rallybio Trading Down 0.4%

Shares of NASDAQ RLYB opened at $14.46 on Friday. Rallybio has a 12-month low of $2.16 and a 12-month high of $16.00. The stock has a market capitalization of $76.64 million, a price-to-earnings ratio of -3.33 and a beta of -1.10. The firm’s 50-day moving average price is $10.81 and its 200-day moving average price is $7.72.

Rallybio (NASDAQ:RLYB – Get Free Report) last released its quarterly earnings data on Wednesday, May 13th. The company reported ($1.46) earnings per share for the quarter, missing analysts’ consensus estimates of ($1.20) by ($0.26). The firm had revenue of $0.21 million during the quarter, compared to analysts’ expectations of $0.21 million. Rallybio had a negative net margin of 911.07% and a negative return on equity of 55.79%.

About Rallybio

(Get Free Report)

Rallybio Therapeutics, Inc (NASDAQ: RLYB) is a clinical‐stage biotechnology company focused on developing and commercializing therapies for people living with rare genetic diseases. The company’s scientific approach leverages diverse modalities—including monoclonal antibodies, small molecules and enzyme replacement—to address high‐unmet‐need conditions in areas such as immunodeficiency, metabolic disorders and dermatologic diseases. Rallybio’s pipeline is designed to advance through registrational clinical trials with the goal of delivering first‐in‐class or best‐in‐class therapies to patients who currently have limited or no approved treatment options.