Does Alexa always show historical ranks for sites?

No, on alexa.com we only show historical global ranks for sites in the top 1 million. We do not show historical country ranks or historical global ranks for sites outside of the top 1 million.

The reason that we do not show historical ranks for sites outside of the top 1 million is because we have found the data for those sites to be extremely sparse. When we have very limited data for a site, the site's ranks will tend to fluctuate to such a degree that the information is no longer relevant and potentially misleading.

Prior to August 2016 we did attempt to show historical rank data for sites outside of the top 1 million. However, we re-assess our data over time to make sure it provides relevant and helpful insight to our users. In early August 2016, we determined that historical rank data on sites outside of the top 1 million no longer fit this criteria and therefore it was removed.