Today's market summary from Goldman about sums it up:
Though a convincing explanation might be hard to come by, equities posted a serious rally today. Tech leads as those stocks hardest hit of late also bounce the most. This means AAPL adds over 7% on the day. Here’s a fun fact: from Friday’s low to today’s high AAPL rallied over 12% – or about 58bn in market cap. A rally always feels good but that type of volatility is hard to reconcile with a healthy market.
One question for Goldman: what's a "healthy" "market"?