Tandem Diabetes Care, Inc. Securities Lawsuit Investigation

Shamis & Gentile P.A., a law firm that advocates for investors who are victims of securities fraud, is investigating potential claims against Tandem Diabetes Care, Inc. (TNDM).

If you purchased or held Tandem Diabetes Care securities and suffered losses, you may be eligible to join this securities investigation and seek compensation.

About Tandem Diabetes Care

Tandem Diabetes Care is a medical device company focused on the design, development, and commercialization of products for people with diabetes. The company is best known for its t:slim X2 insulin pump, which is marketed as a technologically advanced device for insulin delivery and continuous glucose monitoring integration (www.sec.gov).

The t:slim X2 pump is a flagship product, and Tandem Diabetes Care has highlighted its focus on innovation and expanding its product portfolio through new features and technology. The company has also raised significant capital, including a $275 million convertible note offering in March 2024, which was intended to support ongoing business initiatives (investor.tandemdiabetes.com).

Potential Concerns Under Investigation

Lawyers are investigating whether Tandem Diabetes Care may have made misleading statements or omitted material information regarding the safety and reliability of its t:slim X2 insulin pumps. On Aug. 7, 2025, the company announced a “voluntary medical device correction” for the t:slim X2 due to a speaker-related defect. This defect, known as “Malfunction 16,” can cause the pump to stop delivering insulin and sever communication with continuous glucose monitoring (CGM) devices, potentially resulting in high blood sugar and even hospitalization. At the time of the disclosure, Tandem Diabetes Care reported 700 confirmed adverse events and 59 injuries, though no deaths were noted (investor.tandemdiabetes.com).

The Aug. 7, 2025 announcement appears to have been the first public disclosure of this specific defect. Prior to this, Tandem Diabetes Care had issued unrelated corrections, such as a March 2024 recall of its mobile app for battery issues, but had not informed investors or the public about the speaker defect affecting the t:slim X2 pump (www.sec.gov).

Following the disclosure on Aug. 7, 2025, Tandem Diabetes Care’s stock price dropped 19.9 percent, or about $2.87 per share. With approximately 66.5 million shares outstanding, this represented a loss of roughly $190 million in market capitalization. Notably, this decline occurred on a day when the broader market was essentially flat, indicating the drop was specific to Tandem Diabetes Care’s announcement rather than a market-wide event (www.cnbc.com).

Legal professionals may review whether Tandem Diabetes Care’s public statements during the class period, including earnings calls and press releases, adequately disclosed the risks associated with its products. For example, in August 2024, CEO John Sheridan highlighted “strong demand for our latest technology” and “early enthusiasm for our expanding portfolio,” with no mention of any reliability issues. Similar positive statements about sales growth and product safety were made in subsequent quarters, including the Q3 2024 and Q4 2024 financial releases (investor.tandemdiabetes.com, investor.tandemdiabetes.com, investor.tandemdiabetes.com). In none of these communications did the company disclose the existence of the pump defect or the reported adverse events.

Attorneys could investigate if the company’s statements about the t:slim X2 pump’s ability to “reliably and securely communicate” with CGM and dosing devices were misleading, given that the speaker defect could terminate both communication and insulin delivery (investor.tandemdiabetes.com, investor.tandemdiabetes.com). The investigation may focus on whether these omissions and affirmations of safety were misleading in light of the eventual revelation of the defect.

Lawyers may also examine whether Tandem Diabetes Care’s management was aware of the defect prior to the public disclosure. The t:slim X2 pump is a core product for the company, and the magnitude of the issue—hundreds of thousands of pumps in use, 700 adverse events, and 59 injuries—suggests that senior executives may have been aware of the risks. The fact that the company had already experienced a significant product issue in March 2024 further raises questions about management’s knowledge of potential vulnerabilities (www.sec.gov).

Insider trading does not appear to be a significant concern in this case. Directors Kim Blickenstaff and Dick Allen made modest sales during the class period, while COO Jean-Claude Kyrillos purchased shares in March 2025. No CEO or CFO sales were identified, and the total proceeds from insider sales were small relative to the company’s market capitalization (www.insidertrades.com). This pattern does not suggest a classic insider “dump” ahead of negative news.

The proposed class period for this investigation is from Aug. 1, 2024, through Aug. 7, 2025. This timeframe covers when the potentially misleading statements were made and ends with the public disclosure of the defect (investor.tandemdiabetes.com, investor.tandemdiabetes.com).

Your Rights and Next Steps

Investors who purchased Tandem Diabetes Care securities between Aug. 1, 2024 and Aug. 7, 2025 and suffered losses may have important legal rights. This is currently an investigation, not a filed lawsuit. If the investigation uncovers evidence of securities fraud or other violations, a class action lawsuit may be filed on behalf of affected shareholders.

Lawyers are ready to help investors understand their options, including how to participate in any potential future class action. Investors who held shares during the class period and experienced losses tied to the Aug. 7, 2025 stock drop could be eligible to recover damages. It is important to act promptly, as securities investigations and lawsuits are subject to strict deadlines.

You May Be Entitled to Compensation

If you purchased Tandem Diabetes Care securities and suffered losses, you may be eligible to join this investigation and seek compensation for your financial harm. Securities investigations are time-sensitive, and acting quickly can help preserve your rights.

To learn more about your options and to join the investigation, complete the form below.