In a significant blow to Humana (HUM), the US health insurer's stock took a sharp 12% plunge on Thursday. The cause behind this decline was the company's report of a surge in older patients seeking care, which is expected to adversely impact its fourth quarter results.

Under the Affordable Care Act, companies are mandated to maintain a Medical Loss Ratio (MLR) of at least 80-85% each year. The MLR is calculated by subtracting the amount paid out in claims from the medical premiums collected by an insurer. Humana's report has raised concerns not only for its own stock but also for other Medicare Advantage insurers such as CVS (CVS) and United Healthcare (UNH), who are yet to release their earnings reports.

Healthcare sector specialist Jared Holz from Mizuho observed that Humana's numbers are continuing a post-pandemic trend that was initially expected to diminish by this point. Holz stated, "This is the most significant negative variance we can recall and speaks to the still higher than usual healthcare utilization environment particularly among the older population(s) across the country."

He further emphasized that as medical procedures and utilization rates remain high, medical device stocks can expect a boost. This implies that surgeries and other medical procedures are anticipated to increase as a result of the heightened healthcare utilization in older patients.

While the impact on Humana has been significant, JPM analysts noted in a recent report that other Medicare Advantage players like Cigna (CI) and Centene (CNC) may not be as heavily affected, given their lower market share.

The report of increased healthcare utilization among older patients has brought forth both challenges and potential opportunities for the health insurance industry. As market players analyze and respond to these trends, it remains to be seen how other insurers will fare in the face of a similar scenario, and whether the surge in patient care demand will subside as the world navigates a post-pandemic reality.