The U.S. Securities and Exchange Commission (SEC) is reviewing whistle-blowers' allegations that Aflac Inc. may have misled investors in reporting its financial results, according to two people familiar with the matter.

The complaint filed with the SEC on behalf of former workers accuses the Columbus, Georgia-based insurer of inflating a measurement of how many associates were making sales and suggests the firm possibly manipulated earnings by shifting the timing of when it booked revenue, according to one of the people and the document, which was reviewed by Bloomberg News.

“These allegations were made public several months ago, and have been thoroughly investigated by external independent counsel, which found them to be without merit and immaterial,” Teresa L. White, the president of Aflac U.S., said in a statement to Bloomberg News. “We have been transparent on this matter, posting detailed independent reports on our website and providing these reports to the SEC and other regulators. To date, we have received no requests for information from the SEC pertaining to its review of these matters.”