SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 _________________________________________________________________ FORM 10-K _________________________________________________________________ ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2025 or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number 001-36189 ____________________ ...

Media Contact: 858-366-6900 media@tandemdiabetes.com Investor Contact: 858-366-6900 IR@tandemdiabetes.com Exhibit 99.1 FOR IMMEDIATE RELEASE Tandem Diabetes Care Announces Fourth Quarter and Full Year 2025 Financial Results and 2026 Financial Guidance San Diego, February 19, 2026 - Tandem Diabetes Care, Inc. (Nasdaq: TNDM), a global insulin delivery and diabetes technology company, today reported its financial results for the quarter and fiscal year ended December 31, 2025 and provided its financial guidanc ...

Core Insights - Tandem Diabetes Care, Inc. (TNDM) is expected to report a quarterly loss of -$0.05 per share, marking an 88.6% increase in loss compared to the same period last year [1] - Analysts forecast revenues of $276 million, reflecting a year-over-year increase of 9.3% [1] - The consensus EPS estimate has been adjusted downward by 0.8% over the past 30 days, indicating a reassessment by covering analysts [1] Revenue Estimates - Analysts project 'Revenue- Supplies and Other' to reach $141.55 million, indicating a year-over-year change of +10.4% [4] - The consensus for 'Revenue- Pump' is estimated at $134.50 million, showing an increase of +8.3% from the prior-year quarter [4] - 'Sales- Pump- United States' is expected to be $108.34 million, reflecting a year-over-year change of +10.1% [4] Geographic Sales Projections - 'Sales- Pump- Outside the United States' is estimated to be $26.16 million, indicating a +1.5% change from the year-ago quarter [5] - 'Sales- Supplies and Other- United States' is forecasted to reach $94.74 million, with a year-over-year change of +10.3% [5] - The estimated 'Geographic Sales- United States' stands at $203.09 million, reflecting a year-over-year change of -5.4% [5] International Sales Estimates - 'Sales- Supplies and Other- Outside the United States' is projected at $46.80 million, indicating a +10.6% change from the prior-year quarter [6] - The consensus for 'Geographic Sales- Outside the United States' is $72.94 million, showing a significant decline of -99.9% from the year-ago quarter [6] Pump Shipments Forecast - Total worldwide 'Pump Shipments' are expected to reach 35,032, compared to 34,000 in the same quarter last year [7] - 'Pump Shipments- Outside the United States' is projected at 9,400, down from 10,000 in the previous year [7] - 'Pump Shipments- United States' is estimated at 25,632, compared to 24,000 in the year-ago period [7] Stock Performance - Over the past month, shares of Tandem Diabetes Care have returned -6%, while the Zacks S&P 500 composite has changed by -1.4% [8] - TNDM currently holds a Zacks Rank 3 (Hold), suggesting its performance may align with the overall market in the near future [8]

Core Viewpoint - Rosen Law Firm is investigating potential securities claims on behalf of shareholders of Tandem Diabetes Care, Inc. due to allegations of materially misleading business information issued by the company [1]. Group 1: Legal Action and Investor Rights - Shareholders who purchased Tandem Diabetes securities may be entitled to compensation through a class action lawsuit without any out-of-pocket fees [2]. - The Rosen Law Firm is preparing a class action to seek recovery of investor losses related to Tandem Diabetes [2]. Group 2: Company Incident and Stock Impact - On August 7, 2025, Tandem Diabetes issued a press release regarding a voluntary medical device correction for select t:slim X2 insulin pumps, which stated a potential speaker-related issue could lead to insulin delivery discontinuation [3]. - Following this announcement, Tandem Diabetes' stock experienced a significant decline of 19.9% on the same day [3]. Group 3: Rosen Law Firm's Credentials - The Rosen Law Firm has a strong track record in securities class actions, having achieved the largest securities class action settlement against a Chinese company and being ranked No. 1 for securities class action settlements in 2017 [4]. - The firm has recovered hundreds of millions of dollars for investors, including over $438 million in 2019 alone [4].

Core Viewpoint - Rosen Law Firm is investigating potential securities claims on behalf of shareholders of Tandem Diabetes Care, Inc. due to allegations of materially misleading business information issued by the company [1]. Group 1: Legal Action and Investor Rights - Shareholders who purchased Tandem Diabetes securities may be entitled to compensation through a contingency fee arrangement, with no out-of-pocket costs [2]. - Rosen Law Firm is preparing a class action to seek recovery of investor losses [2]. Group 2: Company Incident and Stock Impact - On August 7, 2025, Tandem Diabetes issued a press release regarding a voluntary medical device correction for select t:slim X2 insulin pumps, addressing a potential speaker-related issue that could lead to insulin delivery discontinuation [3]. - Following this announcement, Tandem Diabetes' stock experienced a significant decline of 19.9% on the same day [3]. Group 3: Rosen Law Firm's Credentials - Rosen Law Firm has a strong track record in securities class actions, having achieved the largest securities class action settlement against a Chinese company and being ranked No. 1 for securities class action settlements in 2017 [4]. - The firm has recovered hundreds of millions of dollars for investors, securing over $438 million in 2019 alone [4].

Core Viewpoint - Rosen Law Firm is investigating potential securities claims on behalf of shareholders of Tandem Diabetes Care, Inc. due to allegations of materially misleading business information issued by the company [1]. Group 1: Company Information - Tandem Diabetes Care, Inc. is facing scrutiny after a press release on August 7, 2025, announced a voluntary medical device correction for select t:slim X2 insulin pumps, which could lead to a discontinuation of insulin delivery due to a speaker-related issue [3]. - Following the announcement, Tandem Diabetes' stock experienced a significant decline of 19.9% on the same day [3]. Group 2: Legal Actions - Investors who purchased Tandem Diabetes securities may be eligible for compensation through a class action lawsuit being prepared by Rosen Law Firm, which operates on a contingency fee basis [2]. - The firm emphasizes the importance of selecting qualified legal counsel with a proven track record in securities class actions, highlighting its own success in recovering substantial amounts for investors [4]. Group 3: Firm's Credentials - Rosen Law Firm has achieved notable recognition, including the largest securities class action settlement against a Chinese company and being ranked No. 1 for securities class action settlements in 2017 [4]. - The firm has consistently ranked in the top 4 for securities class action settlements since 2013 and has recovered hundreds of millions of dollars for investors, including over $438 million in 2019 alone [4].

Market Overview - U.S. equity markets in Q4 2025 were influenced by optimism regarding potential monetary easing and caution related to economic growth and valuations [1] - Early gains were attributed to strong AI-related earnings and a rate cut by the US Federal Reserve in October, but sentiment cooled later due to mixed signals from the Fed [1] - Large caps rose 17.4% for the year and 2.4% in the quarter, while small caps gained 12.8% for the year and 2.2% in the quarter [1] - Value stocks outperformed growth stocks, returning 3.3% versus 1.2% for the quarter [1] Fund Performance - Meridian Growth Fund delivered a return of -0.39% (net) in Q4 2025, underperforming the Russell 2500 Growth Index's return of 0.33% [1] - The firm is monitoring factors that may impact market returns, including changes in monetary policy and the sustainability of AI investments due to high valuations among hyperscalers [1] Company Spotlight: Tandem Diabetes Care, Inc. - Tandem Diabetes Care, Inc. (NASDAQ:TNDM) was highlighted as a leading contributor in the Meridian Growth Fund's Q4 2025 investor letter [2] - The company specializes in technology solutions for diabetes management, particularly advanced insulin delivery systems [3] - Tandem's stock traded between $9.98 and $37.93 over the past 52 weeks, closing at $20.20 on January 26, 2026, with a market capitalization of $1.37 billion [2] - The stock experienced a one-month return of -10.26% but gained 33.77% over the last three months [2] - The company is well-positioned to capture market share in a growing addressable market, as many Type 1 diabetes patients still manage insulin manually [3]

Core Viewpoint - Rosen Law Firm is investigating potential securities claims on behalf of shareholders of Tandem Diabetes Care, Inc. due to allegations of materially misleading business information issued by the company [1]. Group 1: Legal Action and Investor Rights - Shareholders who purchased Tandem Diabetes securities may be entitled to compensation through a contingency fee arrangement, with no out-of-pocket costs [2]. - A class action is being prepared by Rosen Law Firm to seek recovery of investor losses [2]. Group 2: Company Incident and Stock Impact - On August 7, 2025, Tandem Diabetes issued a press release regarding a voluntary medical device correction for select t:slim X2 insulin pumps, addressing a potential speaker-related issue that could lead to insulin delivery discontinuation [3]. - Following this announcement, Tandem Diabetes' stock experienced a significant decline of 19.9% on the same day [3]. Group 3: Rosen Law Firm's Credentials - Rosen Law Firm emphasizes the importance of selecting qualified legal counsel with a successful track record in securities class actions [4]. - The firm has achieved notable settlements, including the largest securities class action settlement against a Chinese company and has consistently ranked highly in securities class action settlements since 2013 [4]. - In 2019, the firm secured over $438 million for investors, showcasing its capability in recovering substantial amounts for clients [4].

Core Viewpoint - Rosen Law Firm is investigating potential securities claims on behalf of shareholders of Tandem Diabetes Care, Inc. due to allegations of materially misleading business information issued by the company [1]. Group 1: Company Information - Tandem Diabetes Care, Inc. is facing scrutiny after a press release on August 7, 2025, announced a voluntary medical device correction for select t:slim X2 insulin pumps, which could lead to a discontinuation of insulin delivery due to a speaker-related issue [3]. - Following the announcement, Tandem Diabetes' stock experienced a significant decline of 19.9% on the same day [3]. Group 2: Legal Actions - Investors who purchased Tandem Diabetes securities may be eligible for compensation through a class action lawsuit being prepared by Rosen Law Firm, with no out-of-pocket fees required [2]. - Interested investors can join the class action by submitting a form or contacting the law firm directly for more information [2]. Group 3: Rosen Law Firm Credentials - Rosen Law Firm has a strong track record in securities class actions, having achieved the largest securities class action settlement against a Chinese company and being ranked No. 1 for the number of settlements in 2017 [4]. - The firm has recovered hundreds of millions of dollars for investors, securing over $438 million in 2019 alone [4].

Core Viewpoint - Tandem Diabetes Care, Inc. is a prominent player in the insulin pump technology market, showing resilience against competition from major companies like Medtronic and Insulet Corporation [1] Company Performance - RBC Capital maintains an "Outperform" rating for Tandem Diabetes, raising its price target from $25 to $30, reflecting confidence in the company's growth potential [2] - The average twelve-month price target from brokerages is approximately $22.44, slightly below the current stock price of $23.03, indicating a modest increase of 1.90% or $0.43 [3] Analyst Sentiment - Analyst ratings for Tandem Diabetes show mixed sentiment: one "sell," eleven "hold," and five "buy" recommendations [3] - Stifel Nicolaus initiated coverage with a "hold" rating and a target price of $15.00, while Canaccord Genuity reaffirmed a "buy" rating with a price objective of $24.00 [4] Stock Performance - The stock has fluctuated between a low of $22.40 and a high of $23.10 during the day, with a yearly peak of $38.28 and a low of $9.98 [5] - Tandem Diabetes Care has a market capitalization of approximately $1.56 billion and a trading volume of 120,728 shares on the NASDAQ exchange [5]