Credit Suisse and the U.S. Securities and Exchange Commission (SEC) engaged in a months-long debate over the severity of reporting deficiencies that led the Swiss bank to delay its annual report last month.

Credit Suisse said in March it had postponed the annual filing after a "late call" with the regulator which raised questions about earlier financial statements.

Correspondence published in the SEC's online database on Tuesday show that agency staff first raised questions with Credit Suisse officials in July 2022.

Credit Suisse and the SEC declined to comment.

At issue were changes Credit Suisse made to how it booked a series of cash flows, including share-based compensation and foreign exchange hedges, and if control deficiencies needed to be disclosed to its audit committee or escalated to investors.

"Management believes it is prudent to briefly delay the publication of its accounts in order to understand more thoroughly the comments received," Credit Suisse said at the time of the delay on March 9.

The last-minute delay concerned analysts and sent Credit Suisse shares to near an all-time low. The back-and-forth between the bank and the U.S. regulator extended into another week as turmoil gripped the banking sector.

As recently as March 10, the SEC asked the bank to explain how it decided that an "entity-level material weakness did not exist" for its 2021 and 2022 financial years.

Material weaknesses are considered the most serious of such control failures. In previous letters to the SEC in August and November, Credit Suisse's former chief financial officer David Mathers and his successor Dixit Joshi described the failings as "deficiencies", which are considered to be less serious.

In the March 10 letter to Joshi, SEC staff acknowledged discussions with the bank on March 8-10. Joshi responded on March 12, saying in a letter that the firm noted the concerns and had reassessed its position.

"We will report that we have, and have had, a material weakness in internal control over financial reporting..." he said in the letter posted on the SEC online database.

Credit Suisse notified shareholders of the weaknesses in its annual report on March 14, the day before it was granted a liquidity lifeline by the Swiss National Bank.

This proved insufficient and on March 19, the bank's takeover by Swiss rival UBS was announced.

The Credit Suisse takeover dramatically changes the financial landscape in the wealthy Alpine country
AFP