Sasfin's experience shows how damaging 'rogue' bankers can be and demonstrates that the line between formal and underground financial systems is often merely hypothetical.

This year, Sasfin Bank seemingly declared defeat after a series of scandalous revelations about the deep rot in its foreign exchange business.

Facing a multibillion-rand damages claim from SARS for allegedly facilitating what appears to have been rampant money laundering, the bank first announced that it would remove itself from the Johannesburg Stock Exchange and then that it would simply stop being a bank altogether.

Meanwhile, it still maintains that its woes stem from proverbial bad apples - individual employees that need to be brought to book.

However, AmaBhungane has obtained years of records for Sasfin's forex accounts at FNB and Nedbank - places where it pools clients' funds before sending them abroad. We also have internal data on the bank's clients.

Put together, these documents, which stretch back a decade, show how Sasfin's forex department ran amok as long ago as 2014.

This extends beyond cases and individuals already made public by SARS' recent attempt to hold Sasfin accountable for its trades on behalf of dodgy clients (which we reported on previously).

If nothing else, Sasfin's accounts show how brokers and staff courted clients that should, on the face of it, never have made it past even...