As you can see, since early January 2017, when Altaba Inc. ($AABA) crossed the 50 Moving Average to the upside, it remained in a clear uptrend, nicely above the aforementioned 50MA and the RSI remained in a bullish zone... all up until October 25th...
On that day, the price has crossed the 50MA to the downside, the RSI has also reached a lower level not seen since early January 2017 and on top of that the last three higher highs in the price, were not confirmed by the RSI, which had lower highs in each instance, creating a so called bearish divergence.
It will be very interesting to watch what unfolds in the next few days/weeks. It does not need to be outright bearish, but does indeed indicate a change in the rate (steepness) of the uptrend.
If you are long $AABA, caution is warranted.