Amazon, Microsoft dip; EU probes AWS, Azure cloud services

** Shares of Amazon AMZN down 3.3% at $225.3 after EU launches probe into AWS cloud services under Digital Markets Act (DMA)

** Microsoft MSFT down 2.6% at $494.3; the European Commission also targets Azure in the investigation

** European Commission opens three investigations: two to assess if AWS and Azure should be designated as gatekeepers, and one to test DMA's effectiveness in curbing anticompetitive practices in cloud computing sector

** Amazon's AWS is world's largest cloud provider, followed by Microsoft's Azure and Alphabet's GOOG Google Cloud

** "We will also look at whether the DMA’s existing rules need to be updated so Europe can keep pace with fast-evolving practices in the cloud sector," EU antitrust chief Teresa Ribera said in a statement.

** MSFT spokesperson said the company was ready to contribute to the enquiry, while an AWS spokesperson said "designating cloud providers as gatekeepers isn't worth the risks of stifling invention or raising costs for European companies"

** Rothschild & Co Redburn downgraded MSFT and AMZN to 'neutral' from 'buy'

** Separately, AMZN is on track to raise $15 bln in its first U.S. bond sale to fund its AI infrastructure