CDS and debt are not really inefficient markets. Some bonds are less liquid than others but there is currently a rapid conversion to electronic trading going on. CDS is also a very mature market. Not saying that those markets don't contain signal but they are not very inefficient.
and I think the lack of this perpetuates market inefficiencies. I think insights into CDS can be a leading indicator into equities and equity futures, yet CDS are restricted to OTC markets in the US
CDS isn't an OTC instruments. Swaps are now traded on SEFs like MarketAxess or TradeWeb. Just because you don't have access to the data don't think that professionals don't. But this isn't OHLC data for listed equities. Expect to pay. Actually high quality realtime equity data (ITCH,PITCH,OpenBook Ultra,etc...) costs real money as well.
Who's going to provide that data for free when they can charge a LOT of money for access to it. Ever notice why free data on Google or Yahoo are 15 min delayed?
I know what the exchanges charge for data access, and even if you pay it is in an antiquated format.
Tradier has been providing equity and option tick data for free for years in a clean RESTful API with the capability of websockets and streaming. So thats the answer to your question of who.
Thats part of their business model. I have not used their data but I can tell you that all tick data is not created equally.
We are unlikely to ever see CDS data for free since individuals cannot trade them as most retail investors are not Eligible Contract Participant. Some brokerages give away data to get people to trade with them so there its about customer acquisition.
