Oil prices

4:30 pm : Stocks may have closed with substantial losses Friday, but the extent of the downturn was far better than many initially feared.

Index futures were limit down ahead of the session's opening bell, which occurs when trading is halted in order to pace losses amid frantic selling efforts. That had participants spooked and anticipating a large scale sell-off.

4:40 pm : The week's wild ride has concluded, but onlookers might not know it by the relatively mild close had on Friday. The S&P 500 surged almost 12% Monday, suffered its biggest drop since the 1987 crash on Wednesday, and rallied more than 4% Thursday. On Friday alone the index swung nearly 7% from low to high before finishing with a 0.6% loss.

Few things stir the blood more than Wall Street firms getting into a good old scrap. Put aside the internecine squabbling at Morgan Stanley - they don't come much better than the current dust-up between Citigroup (metals "super cycle") and Goldman Sachs (oil "super spike"), and Merrill Lynch - whose chief equity strategist, David Bowers, on Monday poured water on the idea of what he described as a resources bubble.