FORTUNE — Minutes after Tim Cook wrapped up the media event at which the iPhone 5 was unveiled, Apple (AAPL) fell to its low of the day — $656 a share.
On Friday morning — less than two days later — the stock opened at $689.97 and at 12:23 p.m. briefly touched a record intraday high of $696.98 — up $40.98 (6.25%) from Wednesday’s low.
The net effect was to add $38.4 billion to Apple’s market capitalization.
The stock gave up some of its gains in afternoon trading, but when it closed at $691.28, up $8.30 (1.22%) for the day, it had set yet another all-time record.
Much of the rest of the market is also up this week, of course. But not that much.
Apple was already the most valuable company in the world. With a market cap of over $647 billion at the close, it’s even more so today.
See also: Pre-orders for Apple’s iPhone 5 sell out in less than an hour.