(Reuters) — Credit Suisse has postponed the publication of its annual report after a last-minute call from the U.S. Securities and Exchange Commission, which raised questions about its earlier financial statements.

The unusual intervention by the U.S. regulator is the latest blow to Credit Suisse as it attempts to rebuild investor confidence after a series of scandals and setbacks that have sent its shares plunging and led clients to withdraw billions.

Credit Suisse shares were close to their all-time low in Zurich on Thursday but later recovered much of a 6% loss.

The Zurich-based bank said the SEC had called it late on Wednesday regarding “certain open SEC comments about the technical assessment of previously disclosed revisions to the consolidated cash flow statements in the years ended December 31, 2020, and 2019, as well as related controls.”

The bank had revised how it booked a series of cash flows, including share-based compensation and foreign exchange hedges.

Credit Suisse said that following the call it had decided to postpone publication of its 2022 annual report.

“Management believes it is prudent to briefly delay the publication of its accounts in order to understand more thoroughly the comments received,” it said, adding that the 2022 financial results "are not impacted."

The SEC declined to comment on the matter.

It remains unclear when the annual report will be released and the Credit Suisse announcement concerned analysts.

“(It) does not help investor sentiment and it does not help in rebuilding trust,” said Andreas Venditti from Vontobel.

In February, Credit Suisse reported that 2022 brought its biggest annual loss since the 2008 global financial crisis after rattled clients pulled funds from the bank, and it warned that a further "substantial" loss would come this year.

Credit Suisse, Switzerland's second-biggest bank, was hard hit by the collapse of U.S. investment firm Archegos in 2021 as well as the freezing of billions of supply chain finance funds linked to insolvent British financier Greensill.

The bank was also rocked by a prosecution in Switzerland involving laundering money for a criminal gang.

Meanwhile, credit ratings agency Standard & Poor's downgraded Credit Suisse to just one level above so-called junk status in November.