Penny Stocks on the Move: Today’s Top Gainers and Biggest Decliners

On September 18, 2025, penny stocks exhibited notable volatility, with Adaptimmune Therapeutics Plc (ADAP) surging 97.53% as the day's top gainer while Replimune Group, Inc. (REPL) plummeted 39.41% as the steepest decliner.

Top Gainers
Adaptimmune Therapeutics Plc (ADAP): Spectacular 97.53% Leap Leads Penny Stocks
Adaptimmune Therapeutics Plc (ADAP) surged 97.53% today, ranking as the top gainer in the penny stock market. Its intraday high reached $0.179 before closing at $0.16. The company operates within the Pharmaceuticals industry. No qualifying news items directly contributing to today's surge were reported within the required five-day window preceding September 18, 2025. Recent significant corporate actions, including the sale of its cell therapy portfolio, occurred outside this timeframe.

Cardlytics, Inc. (CDLX)
Cardlytics, Inc. (CDLX), operating in the Professional Services industry, saw its stock surge 92.66% today, ranking as the second biggest gainer in the penny stock market. The stock reached an intraday high of $3.16 before closing at $2.755. Recent developments likely fueling this significant move include the company reporting second-quarter financial results on August 6, 2025. The announcement, followed by the company being named "Best Digital Ad Network" in the 2025 MarTech Breakthrough Awards on August 14, 2025, provided a positive catalyst.

Laser Photonics Corporation (LASE)
Laser Photonics Corporation (LASE), operating in the Electrical Equipment industry, surged 68.21% today, ranking as the third-largest gainer in the penny stock market. Shares reached an intraday high of $5.88 before closing at $4.71. The company's significant stock movement follows a shareholder letter released today highlighting growth strategies and technological advancements, including discussions around its Laser Shield Anti-Drone System. Additionally, recent reports indicate the company's selection as a finalist in a notable Defense Innovation Challenge on September 18, coinciding with the prior announcement of Q2 2025 revenue growth exceeding 300%, detailed in financial results also released on September 18.

Aeries Technology, Inc. (AERT)
Aeries Technology (AERT) surged 63.73% on heavy volume, ranking as the fourth biggest gainer in today's penny stock market. The stock hit an intraday high of $1.20 before closing at $0.93. The company operates in the Professional Services sector. Reports indicate Aeries signed a significant multi-year contract worth up to $8 million annually on September 18th to expand AI capabilities and its India footprint for a global client. This follows its recent September 8th announcement detailing a strategic expansion plan targeting 500+ new roles in India and Mexico.

Aptevo Therapeutics Inc. (APVO)
Aptevo Therapeutics, a biotechnology company, surged 40.43% today—ranking 5th among penny stocks—with shares reaching an intraday high of $2.55 before closing at $1.98. The spike follows reports on September 16 of a 100% remission rate in a cohort of its Phase 1b/2 RAINIER trial for acute myeloid leukemia, with its drug candidate mipletamig showing no severe side effects; analysts suggest these breakthrough results are driving intense investor optimism.

Top Decliners
Replimune Group, Inc. (REPL)
Replimune Group, Inc. (REPL), a Biotechnology sector stock, plunged 39.41% today, the largest percentage decliner among penny stocks. The stock hit an intraday low of $3.12 before closing at $3.46. Today's sharp decline follows news indicating the company will not pursue accelerated FDA approval for its therapy based on current data and follows an update from a recent meeting with regulators. Concurrently, multiple securities class action lawsuits have recently been filed against the company concerning its trial design and disclosures.

Atlasclear Holdings, Inc. (ATCH)
Atlasclear Holdings, Inc. (ATCH), operating in the Financial Services industry, plunged 27.78% today—the second-largest decline among penny stocks—hitting an intraday low of $0.858 before closing at $1.165. Recent announcements contributed to the volatility; the company secured $3 million in financing on September 17, triggering a 50% surge yesterday, but subsequent profit-taking and dilution concerns fueled today's sharp selloff.

Wheeler Real Estate Investment Trust, Inc. (WHLR)
WHLR shares plummeted 25.96%, ranking as the day's third-largest decliner among penny stocks, closing at $1.54 after touching an intraday low of $1.48. The Retail REIT announced a 1-for-5 reverse stock split effective September 22, significantly reducing outstanding shares. Reports also indicate a recent exchange of preferred stock for 253,000 common shares on September 16, contributing to investor concerns over dilution and restructuring efforts.

Biocardia, Inc.(BCDA)
Biocardia, Inc. (BCDA), a biotech company, experienced a significant decline today, plummeting 23.78% to rank as the fourth-largest loser in the penny stock market. The stock reached an intraday low of $1.00 before closing at $1.17. Reports indicate the company priced a $6 million public offering this week, a move typically dilutive to existing shareholders. Coupled with the release of Q2 2025 results yesterday (September 17, 2025), revealing a net loss of $2.0 million compared to $1.6 million in the prior year period, investor sentiment turned bearish, driving the substantial sell-off.

CDT Equity Inc. (CDT)
CDT Equity Inc. (CDT), a biotechnology firm, plunged 23.69% today, ranking as the 5th largest decliner among penny stocks. It hit an intraday low of $0.642 before closing at $0.686. Today's sharp reversal follows news this week detailing its treasury strategy. Reports indicate CDT executed its authorized cryptocurrency reserve plan on September 17, acquiring 8.65 Bitcoin for $1 million. This substantial non-core asset allocation has fueled investor concern regarding capital deployment and strategic focus.