A former business executive from Monroe County, N.Y., has filed a disability insurance denial lawsuit against Unum, alleging the insurance giant wrongfully denied a legitimate disability insurance claim.

Unum specializes in disability insurance, which is designed to help people when they are rendered temporarily or permanently disabled to the point that they cannot work. Unum controls 40 percent of the market for this type of insurance, and typically reports billions of dollars in yearly revenue.

Plaintiff Kenneth Rabinowitz in his bad faith insurance lawsuit notes he was diagnosed with mantle cell lymphoma, a type of cancer, in 2008. His treatment included a stem cell transplant in 2009, as well as six months of grueling chemotherapy. Since 2008, he asserts that he has been unable to work, according to his denied disability claim lawsuit. Unum initially approved him for long-term disability benefits. However, Unum eventually overturned the decision, denying Rabinowitz’s benefits and triggering a series of appeals.

Rabinowitz’s insurance claim denial lawsuit quotes a doctor who performed a neuro-psychological exam: “Given the high level work in which he [Rabinowitz] was engaged previously, it is advised that his return to that work be delayed indefinitely until he makes substantial progress.” According to the Unum disability benefits lawsuit, the doctor also stated that Rabinowitz suffered from cognitive problems, most likely caused by chemotherapy.

Unum denied Rabinowitz’s final appeal in September 2013. Under a federal law, the Employee Income Retirement Security Act (ERISA), a person can sue a disability insurance provider if the insurer has acted in bad faith, which is denying a legitimate insurance claim. ERISA requires that a policyholder exhaust any internal appeals process before taking this step. Rabinowitz’s Unum lawsuit holds that the denial stemmed from a conflict of interest, specifically that Unum, the company that would be required to pay out the claim, was in charge of determining if Rabinowitz’s disability was legitimate. The disability insurance lawsuit argues that this situation is inherent to Unum’s process, and cites several legal precedents in order to support this claim.