Amazon.com Inc has gained approval from a number of state pharmaceutical boards to become a wholesale distributor, St. Louis Post-Dispatch reported on Thursday, citing public records.

The Post-Dispatch report sent the shares of U.S. pharmacy chains, drug wholesalers and pharmacy benefit manager Express Scripts down.

"It's unclear, though, whether the regulatory filings support speculation that the e-commerce giant is planning a move into the prescription drug delivery business, territory currently dominated by a handful of companies" the Post-Dispatch report said.

"Industry analysts in recent weeks have raised the possibility that Amazon was eyeing this lucrative new business, posing a potential threat to companies like north St. Louis County-based Express Scripts Holding Co."

An Amazon spokesperson said it doesn’t comment on rumors or speculation.

Earlier this month, a source-based report by CNBC said Amazon would decide before Thanksgiving whether to move into selling prescription drugs online.

The ecommerce giant is reported to be in talks with mid-market pharmacy benefit managers and has been hiring talent to assess the drug retailing market for its entry, brokerage firm Leerink had said.