Health Insurance Innovations Inc. posted the greatest increase in short interest relative to shares outstanding among SNL-covered insurance companies between Sept. 15 and Sept. 29.

The percentage of the company's shares held short relative to shares outstanding increased 758 basis points to 29.54% as of Sept. 29. The company also topped the list of most shorted insurance companies during the period.

WellCare Health Plans Inc. saw the greatest decline in short interest relative to shares outstanding among SNL-covered insurance companies. The percentage of the company's shares held short relative to shares outstanding declined 134 basis points to 3.79% as of Sept. 29.