There are 7 commercial vendors for Ada.

https://www.adacore.com/

https://www.ghs.com/products/ada_optimizing_compilers.html

https://www.ptc.com/en/products/developer-tools/apexada

https://www.ddci.com/products_score/

http://www.irvine.com/tech.html

http://www.ocsystems.com/w/index.php/OCS:PowerAda

http://www.rrsoftware.com/html/prodinf/janus95/j-ada95.htm