Cryptocurrency exchange Kraken is under investigation by the U.S. Securities and Exchange Commission for the sale of unregistered securities, according to a Bloomberg report.

The regulator's inquiry is at an advanced stage and could result in a settlement with the San Francisco-based platform in the coming days, the report added.

Kraken declined to comment on the report. The SEC did not immediately respond to a request for comment.

SEC Chair Gary Gensler has previously said that companies that help facilitate transactions in the crypto market should register with the agency just like other market intermediaries.

Kraken's incoming chief executive officer told Reuters in September that the exchange had no plans to register with the SEC as a market intermediary, or to delist crypto tokens that the regulator has labeled as securities.

In November, Kraken agreed to pay $362,000 to the U.S. Treasury Department's Office of Foreign Assets Control to settle civil liability related to apparent violations of sanctions on Iran, and to invest an additional $100,000 in certain sanctions compliance controls. (Reporting by Hannah Lang in Washington; Editing by Andrea Ricci)