Bitcoin miner Riot Platforms (RIOT) is delaying the filing of its annual 10-K report with the Securities and Exchange Commission due to issues raised by its accounting firm about the company's impairment calculations related to its bitcoin assets.

“After assessing the impact of this revised impairment assessment methodology, the Registrant determined that material errors in certain of its financial statements and reports resulted,” Riot wrote in its SEC filing on Thursday.

Specifically, Riot said its previously issued financial statements for 2022, 2021 and 2020 “contained material errors and should not be relied upon.” Riot said it is working hard to revise its results and expects to file its annual report within the 15-day filing extension window. Shares of Riot were down 2.4% in after-hours trading on Thursday.

Earlier this week, fellow miner Marathon Digital (MARA) said it would need to restate portions of its audited 2021 results and unaudited quarter reports from 2022 following an inquiry from the SEC that questioned its method of calculating impairment on digital assets.

Marathon had previously been scheduled to release its 2022 Q4 results after the close of trading on Tuesday, but now has postponed that.