According to who? And what is included? Microsoft has a history of blurring the lines here. I think the only way you get them being equal is by combining internal use and/or their SAAS offerings. I don't think it's a fair comparison if you do that.
Microsoft: $21.2 Amazon: $20.4B
From [1]. That includes Office365 revenue[2]. Excluding that, Azure is about 1/3 the size of AWS[3]
[1] https://www.zdnet.com/article/cloud-providers-ranking-2018-h...
[2] https://techcrunch.com/2017/10/30/aws-continues-to-rule-the-...
[3] https://www.srgresearch.com/articles/cloud-market-keeps-grow...
I think this is a fair and in depth comparison.
redpixie is a MS partner, so I don’t expect it to be fair.
https://www.redpixie.com/blog/iaas-paas-saas
“As a Microsoft Partner, we focus on Microsoft Azure IaaS solutions”