Shares in technology giant Apple have dropped about 4% in New York trading, after boss Steve Jobs took indefinite medical leave.
While Mr Jobs is continuing as chief executive and will be involved in any major decisions, day-to-day running has passed to Tim Cook.
The news came on Monday, a US public holiday, when markets were closed.
Apple shares are also traded in Frankfurt, where they fell 9% on Monday immediately after the announcement.
The share price initially dropped 6% at the opening bell in New York, before immediately recovering.
The movements come ahead of Apple's first-quarter results, due after the close of trading in New York on Tuesday. BBC News
