A recently filed lawsuit alleges that a longtime employee was subjected to age discrimination and retaliatory termination by his employer after nearly twelve years of service. The complaint was submitted by Mark Hall in the United States District Court for the Western District of Michigan on March 18, 2026, naming Tandem Diabetes Care, Inc. as the defendant.
According to the civil action complaint, Hall asserts that he was wrongfully terminated in violation of both the Age Discrimination in Employment Act (ADEA) and the Michigan Elliott-Larsen Civil Rights Act (ELCRA). The filing outlines a series of events beginning in January 2025 when Hall began reporting directly to Melody Fox, who had recently been promoted to Regional Sales Manager. Fox is described as being significantly younger than Hall, who was 61 at the time.
The complaint states that prior to Fox’s supervision, Hall had worked under three different Regional Sales Managers over an eleven-year period without receiving progressive discipline or negative evaluations. Hall claims he was consistently recognized as a top performer nationally within the company and received positive performance reviews. However, after Fox became his supervisor, Hall alleges he experienced what he describes as demeaning treatment and heightened scrutiny over minor issues such as calendar entries and expense reports.
Hall’s legal filing details that Fox allegedly made several comments regarding his age and potential retirement plans. According to the document, Fox asked questions such as “what is your retirement plan” and “how much longer you plan on doing this,” which Hall interpreted as negative considerations about his age and ongoing employment. The complaint further asserts that Hall explicitly raised concerns with Fox on at least two occasions about perceived age-related mistreatment but saw no change in her behavior.
By May 2025, Hall was placed on a 60-day Performance Improvement Plan (PIP), which he contends was pretextual and based on unfounded performance concerns. He argues that despite meeting or exceeding quotas during this period—and providing information disputing Fox’s stated reasons for disciplinary action—he continued to face criticism from management. The complaint describes incidents where Hall says he was admonished for assisting colleagues or for actions previously accepted by other managers.
On or about September 9, 2025, Hall was terminated from his position. He alleges that this decision followed a pattern of disparate treatment targeting older employees within the company. According to the filing, after his termination his job duties were assumed by younger individuals.
The lawsuit presents three counts: wrongful termination due to age discrimination under ADEA; retaliation for expressing concerns about age discrimination under ADEA; and violations of ELCRA for both wrongful termination based on age discrimination and retaliation. The complaint claims that Tandem Diabetes Care failed to investigate or address Hall’s complaints regarding discriminatory treatment before proceeding with termination.
Hall is seeking compensation including back pay, front pay, salary adjustments, bonuses, insurance benefits, training opportunities, promotions or reinstatement where applicable. He also requests actual damages along with liquidated damages meant to punish what he characterizes as willful conduct by the defendant. Additionally, he asks for attorney’s fees and costs associated with bringing the action.
The attorneys representing Mark Hall are Heidi T. Sharp of The Sharp Firm in Clinton Township, Michigan and Adam C. Lease of Karpf, Karpf & Cerutti in Feasterville-Trevose, Pennsylvania (pro hac vice admission pending). The case is identified as Case No. 1:26-cv-00884.
Source: 126cv00884_Mark_Hall_v_Tandem_Diabetes_Complaint_Western_District_of_Michigan.pdf
