Stock markets across Europe and the US had their worst day in several months. In London the main share index fell more than 200 points - the biggest one day points drop in over four years.
Everywhere the gloom was partly a response to new figures underlying the slump in the US housing market. Poor company profits data and a jump in oil prices also played a part. But, perhaps most important, the markets are gripped by worry that banks and investors generally are becoming much less willing to take on risk.
For some time financial institutions have been reeling from an expected 100 billion dollars of losses from low income Americans defaulting on loans to buy their homes. Now there's concern about the corporate debt market - on Wednesday it emerged that banks were unable to find other investors willing to share the risk in a high profile corporate takeover, the 12 billion dollar buy-out of the US car giant Chrysler.
Other planned takeovers could also be in trouble. Analysts are warning of a "global credit crunch" - meaning business could find it hard to raise money. Things aren't anywhere near as bad as that yet - the fear is they may become so.
Mark Gregory, BBC
Stock markets
associations of dealers in shares and/or goods ready for sale or distribution, doing business according to fixed rules
gloom
pessimistic or depressed mood
underlying the slump
being the basis of the sudden decline in trade or business
jump
here, sharp and sudden growth
gripped by
dominated or affected by
to take on risk
here, to invest into businesses or enterprises that aren't financially secure now but may become profitable in the future
reeling from
being seriously affected by
defaulting on loans
here, borrowing money but not being able to pay it back
corporate takeover
when one large company or corporation takes control of another
buy-out
the purchase of a controlling share in a company