Apple, Alphabet and Amazon stock selloff would reduce their market caps by more than $150 billion combined

The selloff in the shares of AAA technology behemoths — Apple Inc., Alphabet Inc. and Amazon.com Inc. — that reported quarterly results overnight are shaving off a combined $158.5 billion from the companies’ market capitalizations. But that loss would be just about 38% of what the $254.5 billion gained the day before earnings were reported. Apple stock
AAPL,
+3.71%
fell 2.4% in premarket trading Friday after earnings were reported late Thursday. While that would cut Apple’s market cap by $57.6 billion, the pre-earnings rally of 3.7% added $85.3 billion. Alphabet’s stock
GOOGL,
+7.28%

GOOG,
+7.27%
fell 3.6% ahead of Friday’s open to reduce its market cap by $49.8 billion, but the Thursday rally of 7.3% had added $93.6 billion. And for Amazon, the stock
AMZN,
+7.38%
shed 4.4% early Friday to cut off $51.1 billion in market cap, but Thursday’s surge of 7.4% had added $75.6 billion. Meanwhile, futures
NQ00,
-1.19%
for the tech-heavy Nasdaq 100 sank 1.1% ahead of Friday’s open, after the index
NDX,
+3.56%
jumped 3.6% on Thursday. The futures
ES00,
-0.65%
for the S&P 500
SPX,
+1.47%
fell 0.6% early Friday.