As the Frankfurt-based bank's shares plumbed all-time lows last month following news that it had gotten itself entangled in two new legal scandals - one related to facilitating tax evasion that purportedly stemmed from the Panama Papers leak, and another related to the bank's provision of clearing services to Danske Bank's Estonia branch, the epicenter of one of the biggest money laundering scandals in European history - news that DB had paid a relatively insignificant 4 million euro settlement to Frankfurt prosecutors over its role in facilitating so-called "cum-ex" trades for clients who used them to falsely claim tax rebates barely registered.

But as has become sadly typical for DB, which has cultivated one of the most ignominious post-financial crisis records for financial improprieties among the world's biggest banks, the settlement wasn't the end of it. And in an explosive report published Friday, reporters for Reuters working with newsroom non-profit Correctiv published details from internal audits commissioned by DB which revealed that employees for the bank were aware of their clients' plans to illegally exploit a loophole in the German tax code - a loophole that was closed back in 2015 - something that was not previously publicly known.

Though Reuters said the audit that it cited, which was prepared by London law firm Freshfields, had been turned over to prosecutors back in 2017, meaning that they probably factored it in to their investigation before deciding on the December settlement, the information revealed that several DB employees coldly calculated the risks associated with facilitating their clients' illegal behavior, and decided to continue with the business.

There are "lots of indications" that some managers discussed "the reputational risks" of Deutsche Bank’s involvement in a share-trading scheme that is the subject of Germany’s biggest post-war fraud investigation, according to a conclusion in one of five internal audits seen by Reuters.

The bank even went so far as to issue tax certificates for withholding taxes that had never been paid.

The bank issued tax certificates for withholding tax that had never been deducted and made loans to clients to allow them to participate in the scheme to claim tax rebates, according to the audits. German prosecutors say the scheme’s participants misled the government into thinking a stock had multiple owners on its dividend payday who were each owed a dividend and a tax credit, according to court documents.

If you're unfamiliar with the mechanics of the "cum-ex" scandal, here's a quick explanation courtesy of the Business Times.

German authorities claim the scheme, which was perpetrated by clients with the help of several global banks, cost the German state some 5.6 billion euros in rebates that should never have been paid. That's right: these banks effectively helped clients steal from Germany's public funds. The audits commissioned by DB focus on the period between 2006 and 2011.

Cum-ex transactions took advantage of how Germany once handled tax refunds on dividends. At the time, certificates used for tax repayments weren't issued centrally. Deals were set up around dividend day in a way that enabled a shortseller of a stock and its actual owner to both get a certificate stating that the dividend tax was paid. While the tax was paid only once, both could use the certificates to claim full refunds, according to the findings. The practice ended in 2012 when Germany revised its tax laws. Banks have come under scrutiny in these probes for various reasons - doing the deals themselves, financing transactions or acting as custodians that issued the certificates. Deutsche Bank has said it didn't participate in cum-ex trades as a shortseller or buyer, but was involved in some of its clients' deals and that it is cooperating with the authorities.

The audit pointed to failings tied to two DB employees who helped facilitate loans to clients who used the money to carry out cum-ex trades. But the bank's managers were also responsible for significant lapses in oversight, according to the audit.

The audit dated April 16, 2015 pointed to "significant failings" in overseeing two traders, Simon Pearson and Joe Penna, who they say acted as middle men between the clients and the bank departments that lent money to fund the cum-ex scheme and issued tax certificates. Pearson and Penna have been suspects in the investigation since at least 2014 for their role in cum-ex trading, according to court documents. The Freshfields audits say the two traders were aware the prime brokerage services were being used to help other companies carry out cum-ex deals. The reports highlighted the role of the traders but also pointed to failures of the bank’s internal controls as well as lapses of “managers” in the global financial markets division. The April 16 report said that the bank’s controls over the trading desk headed by Pearson were too weak and this was a "serious shortcoming."

One specific manager was singled out in the audit as being responsible for the bulk of these oversight failures.

That criticism about oversight is leveled at management generally but it does briefly single out one individual. "Richard Carson was most directly responsible for this shortcoming as the direct supervisor of the manager of the trading desk," the report said. Carson has since left Deutsche Bank. In an email to Reuters he said: "I have not seen, nor have been provided with any copies of the reports you mention in your communication. I would not accept that there was any failings on my part." The report did not implicate him further in the cum-ex scheme.

Fortunately for DB, this information isn't anything prosecutors haven't already seen. But it could suggest that more penalties in the investigation - which is still ongoing - could be forthcoming. And that's bad news for a bank that is struggling with slumping shares, plunging income, and multiplying fears that the raids connected with the Panama Papers money laundering could lead to a massive fine.