Chart: Apple’s wild weekend

April 29, 2013, 4:10 PM UTC

FORTUNE — Can anybody explain what happened to Apple (AAPL) between the close of trading Friday and Monday’s opening bell?

I can almost wrap my mind around the 4.55 million shares traded at exactly 4:00 p.m. Friday and the temporary $3.08 drop one clock tick later. A bunch of Apple weekly options had just expired, and the market had a ton of trades to unwind.

But what’s the significance of that $10.65 vertical spike to $429.20 at 4:00 a.m. Monday, when 1.4 million shares changed hands while the markets were asleep? Was it some kind of signal that only trading insiders — or worse, computer algorithms — can understand?

Note that by noon Monday, Apple’s share price had topped $430, almost as if someone — or some thing — knew eight hours earlier that it was headed there.