Which 1920s German hyperinflation crisis helped wipe out the value of the mark and destabilize markets?

The 1920s German hyperinflation crisis that wiped out the value of the mark and destabilized markets was German hyperinflation.

The crisis developed after World War I, when Germany faced reparations, fiscal deficits, and heavy reliance on borrowing. In 1923, French and Belgian troops occupied the Ruhr after Germany missed reparations deliveries. The German government supported passive resistance there while continuing to pay workers, greatly increasing the money supply.

Prices accelerated at extraordinary speed. A U.S. dollar, worth about 4.2 marks in 1914, reached 4.2 trillion paper marks by November 1923. Savings, wages, pensions, and debts denominated in marks were radically altered; borrowers often benefited while savers lost much of their wealth. The government ended the crisis by introducing the Rentenmark in November 1923 and later stabilizing the currency with the Reichsmark.

Hyperinflation was not exactly a single stock-market crash. It was a currency and economic collapse that severely affected financial markets and is frequently connected with the wider market turmoil of the Weimar Republic.