GENEVA — Switzerland’s market regulator said Thursday it has banned the Swiss affiliate of Russia’s Gazprombank from taking new private clients over money laundering concerns over a 10-year period that emerged from the Panama Papers leak.

The move marks the first and only time that Swiss markets authority, FINMA, identified or penalized any company for wrongdoing after the April 2016 leak, which exposed tax avoidance worldwide — including by some close allies of Russian President Vladimir Putin.

The regulator said it turned up “serious shortcomings in anti-money laundering processes” linked to private clients at Zurich-based Gazprombank Switzerland, which is owned by Gazprombank, a bank founded by natural gas giant Gazprom.

The regulator said it had investigated over 30 Swiss banks after the Panama Papers revelations came out, and “in-depth” investigations took place on about 20. But Gazprombank was the only one it sanctioned.

“FINMA’s investigation, which was completed in January 2018, found that Gazprombank Switzerland was in serious breach of its anti-money laundering due diligence requirements in the period from 2006 to 2016,” it said in a statement.

The regulator pointed to faulty or late categorization of business relationships; a lack of attention to details of the background of those relationships; and failure to properly validate documentation. It said the bank failed to report suspicious relationships to the Swiss money laundering reporting office quickly enough.

The regulator did not provide details, and a spokesman said its job was to entice banks back to lawful and compliant behavior more than to penalize them.

Gazprombank Switzerland, in a statement, said it “accepts FINMA’s decision” taken Monday.

It said the “shortcomings” related “to a large extent” to the time before the Moscow-based bank bought the predecessor operation in 2009. FINMA too said many breaches involved relationships linked to Russian Commercial Bank, as the institution was previously known.

“The bank will strictly monitor the small number of existing private relationships,” the bank statement said. After the Panama Papers were published, its board promptly began an investigation.

“A number of changes have been made in 2016-2017 in order to further enhance compliance with the requirements and best practice standards in Switzerland,” the statement said, without elaborating.

FINMA says it has now concluded its activities linked to the Panama Papers.