US stocks slumped on Friday, dragging down the Dow Jones industrial average by more than 650 points and handing the market its worst week in two years.

Stocks on Wall Street pushed further into record territory today, and the Standard & Poor's 500 index's immaculate start to the year extended to a sixth day.

Apple and other big-name technology stocks got back to their winning ways on Monday and helped drive US indexes once again to record heights.

US stock indexes fluttered up and down on Thursday - then ended the day a fraction above where they started.