According to Google Finance, it appears that Alphabet has a market capitalization of $517B, which is far different than the $558B quoted in the article. This does not appear to be a temporary fluctuation. https://www.google.com/finance?q=NASDAQ%3AGOOGL
Am I missing something? Based on the current market cap numbers on Google Finance, Apple is still higher than Alphabet.
This is based on after-hours trading, where Alphabet is up 9%+ after an earnings beat. The marketcap that you see in Google Finance is calculated based on the price at the end of the trading day, not after-hours trading.
"Alphabet shares (GOOGL) jumped 6% after Google's parent reported estimate-topping fourth-quarter results after the bell. Its combined share classes were then worth $554 billion, surpassing Apple (AAPL), which had a value of about $534 billion and whose shares were down slightly after hours."
Yes, and if you look at the market cap on both of GOOG and GOOGL on Google Finance, you'll note that they are the same (after close -- during trading they seem to be very close but slightly different, probably for timing reasons) and if you do the math, you'll see that for each they aren't reporting the individual cap but the combined cap.
My first reaction was that the problem was one or the other share class being excluded, and then I checked exactly the sources you cite and checked the numbers and realized that couldn't be the problem if.you used Google Finance reported market caps, because they don't report it that way.
Am I missing something? Based on the current market cap numbers on Google Finance, Apple is still higher than Alphabet.