On September 29, 2008, European financial markets experienced steep declines as the global debt crisis that year intensified. Major stock indices across the continent fell sharply, with banking and financial-sector shares among the hardest hit. The rout followed a week of escalating turmoil in international credit markets after the failure of U.S. investment bank Lehman Brothers on September 15 and subsequent emergency interventions and write-downs by major financial institutions. European exchanges opened lower and moved further into negative territory as investors reacted to signs that the credit freeze and losses were spreading. Bank share prices were especially volatile amid mounting concerns over counterparty risk, liquidity strains and possible sovereign exposures tied to support measures for struggling banks. Interbank lending rates and credit-default swap spreads rose, reflecting heightened perceptions of default risk and funding stress. Governments and central banks in Europe responded with a mix of policy measures aimed at stabilising markets and shoring up confidence. Some national authorities announced plans for capital injections, guarantees for bank liabilities and schemes to insure deposits, while the European Central Bank and other central banks provided liquidity support to the banking system. Those interventions sought to restore market functioning, but immediate investor confidence remained fragile as markets reassessed the scale of writedowns and recapitalisation needs. The crisis had several reinforcing channels. Losses tied to U.S. mortgage-related assets and structured products weakened bank balance sheets across borders. The opacity of banks’ exposure to such assets, combined with uncertainty about losses, magnified risk aversion and reduced willingness to lend. Market makers pulled back, trading volumes and liquidity in some instruments thinned, and pricing became more volatile. Sovereign risk considerations also began to surface as governments contemplated large fiscal costs to stabilise the financial sector. The declines on September 29 were part of a broader global sequence of market stress that eroded wealth, curtailed credit availability for businesses and households, and foreshadowed a deeper economic downturn. Policymakers faced the dual challenge of limiting systemic fallout while designing measures that could restore trust in financial counterparties. In subsequent weeks and months, coordinated and national policy actions—including bank rescues, temporary guarantees, asset purchase programmes and monetary easing—sought to arrest the slide, though many economies entered recession and the process of financial repair proved lengthy. Historical assessments of the 2008 crisis emphasise the interplay between private-sector leverage, complex financial instruments, regulatory gaps and procyclical market behaviour. The events of late September 2008, including the market collapse on the 29th, underscored how quickly loss of confidence in a few large institutions can propagate through globalised capital markets, with significant real-economy consequences. Because market moves and policy responses unfolded rapidly, day-by-day details vary across sources; this account focuses on broadly documented market and policy dynamics without attributing specific contemporaneous remarks to individuals. The September 29 market collapse remains a widely cited moment in the 2008 financial crisis timeline, illustrating the acute phase when financial instability became manifest across European markets.