UPDATE says gets Nasdaq violation letter

* Letter says violation relates to unaudited filings

* Has until Jan 18 to submit plan to regain compliance

* Will have independent audit firm review its financials

SAN FRANCISCO, Nov 20 (Reuters) - Inc OSTK.O said on Friday that it has received a letter from the Nasdaq Stock Market informing the online retailer it violated a market listing rule by making an unaudited quarterly financial filing.

Overstock made the disclosure in a regulatory filing with the U.S. Securities and Exchange Commission. The letter, which received on Nov. 19, also said the retailer’s quarterly filing for the period ended Sept. 30 did not contain all the certifications required under the Sarbanes-Oxley Act. said it now has until Jan. 18 to submit a plan to regain compliance with the Nasdaq Listing Rules.

Earlier this month, Overstock sent a letter to shareholders, defending its decision to fire its auditor and make the unusual step of filing an unreviewed quarterly report with regulators. [ID:nN18136553]

Overstock said that to regain compliance, it plans to have an independent audit firm review its financial statements for the periods ending Sept 30. It then plans to file an amendment to its quarterly report to include the reviewed financial statements and necessary certifications.

Reporting by Nicole Maestri; Editing by Richard Chang