Does anyone have good market share data on the various DAWs?

Market share data will be hard to come by. I do see plugin websites routinely list Sonar as one of the DAWs used to test compatibility though. For whatever reason, Pro Tools continues to be the baseline DAW in most pro studios despite its shortcomings and clunky interface. There was a Pro Tools article a few months ago in Sound On Sound about the user's top ten wish list. Sonar had all of those features deployed already!

Most DAW vendors other than Apple and Avid are privately-held companies and therefore not required to release such information, and they don't. Even the companies that are required to make numbers public don't reveal the size of their install base, only the dollar amounts of their revenue. For Apple and Avid, DAW sales are a tiny sliver of their income that might warrant a single line item on their annual reports. Avid, for example, just says that DAW and workstation sales account for about $72 million a year.
 
Of course, online polls exist, but they're pretty useless. 

Cakewalk has worked with a few high market company's like Overloud, Melodyne, VocAlign.
I think something that is overlooked is the work it has done with Microsoft and we are seeing the trickle down effect in new features such as WASAPI, pen, exc support.

In german recording studios you are laughed when you use a computer with Windows. They say only with a MAC you can make professional music. Windows is only for amateuer (they say!)
This is because Apple had the first computers and they came at first into the recording studios. So a lot of german recording studios use MAC. They don't use SONAR because it doesnt run with OSX.
 

AT
... and Avid is just about exclusively Mac.

ProTools is Mac AND Windows. 

Cakewalk had a problem to translate their Windows code to OSX. I think Avid writes their code first in OSX and translate it to Windows. Cakewalk should rewrite the full code in OSX, but this takes a lot of years.
 

Sonar is the only DAW I actually really care about.
 
However, that being said, I'd be truly shocked if they beat out any of these in sales:
 
Fruity Loops
Ableton Live
ProTools
Logic
Studio One
 
If they even break the top 5 in sales, I'd be surprised.  This has nothing to do with how great the product is though.  

As I've said before, this is a very, very small industry. No company has the time to test their products with all DAWs. The testing for, say, plug-ins is the responsibility of the third party...a plug-in company needs to deal with testing on only a limited number of DAWs. A DAW manufacturer can't test a DAW with all available plug-ins.
 
Companies support the DAWs used by the majority of their base. A cross-platform application almost by definition will have more users than a single-platform application. That said, I've known several manufacturers who test with SONAR but don't officially support it. The difference is that if they say they support a DAW, then they need to field support questions from anyone who uses that DAW. It seems any user base is generally unhappy with support, so companies have no desire to increase the number of people who are eligible for support. This is also why some programs work just fine with an older operating system, but a company will say they don't support it.
 

Anderton
As I've said before, this is a very, very small industry. No company has the time to test their products with all DAWs. The testing for, say, plug-ins is the responsibility of the third party...a plug-in company needs to deal with testing on only a limited number of DAWs. A DAW manufacturer can't test a DAW with all available plug-ins.
 
Companies support the DAWs used by the majority of their base. A cross-platform application almost by definition will have more users than a single-platform application. That said, I've known several manufacturers who test with SONAR but don't officially support it. The difference is that if they say they support a DAW, then they need to field support questions from anyone who uses that DAW. It seems any user base is generally unhappy with support, so companies have no desire to increase the number of people who are eligible for support. This is also why some programs work just fine with an older operating system, but a company will say they don't support it.
 

 
Craig
I have seen $200MM several times as estimate of US and $700MM globally.  I understand your comment about "every hardware manufacturer cannot test with every software provider..." or however you said it.  
 
But is this an issue where - like with Softube Console 1 - Sonar and Presonus were up and working day 1 so there was some major effort on the Cake part, and things like UA and Dangerous Music never had a formal outreach from Cake?  Or is it different?  
 
I would assume the market positions are something like (excluding PT, FL and Reason and the low end stuff like Garbage Band)
1   Cubase
2   Logic  (it is so cheap now that apple owns it)
3   Live
4   Sonar???
 
Something like that.  
 
Back to market size...
While $700MM globally is certainly not biotech, semiconductor or automobiles, it is not terrible.  I have worked for the last nearly 30 years in finance with market research always being a big part of my job.  I have seen $100MM Market Cap stocks in industries where the entire market was maybe $100MM and there were 3-4 competitors.  
 
The good thing about software is the variable costs should be low, so high volumes means more cash flow to cover the fixed costs (R&D/Programmers and Marketing I assume in a DAW manufacturer).  In other words, if Sonar is doing $70MM/year (10% of that global market share - just an uneducated guess), it could be a very profitable operation!  And it could afford an outreach.  
 
I have used Cubase and do not see much difference between Sonar and Cubase.  I went with Sonar (or Cakewalk back then) because tech support was better (in the 90s-early 2000s, Cubase Tech Support didn't exist at all!)I currently own Studio 1 and while I like it, i am so much more familiar with Sonar.  Used to have Reason before all the other plugins were available from the zillions of manufacturers out there.  Never had FL except on my iPad.  Didn't care for it.  And I have downloaded Reaper (dont care for) and Live (uh - wtf is this?  I want a virtual tape deck!).  
 
My point is I have tried pretty much everything out there.  I love Sonar.  I hate the lack of BROAD 3rd party support.  I am wondering if this is something that through Gibson they can resolve.  I Pray they move the brand forward and don't Opcode it!
 
 
 
 

Getting meaningful market share numbers is just about impossible because so much software is sold direct. Furthermore when someone buys an interface it probably has a lite version of a DAW. That could be counted as part of market share even though no one uses it.
 
Most estimates of "music software" include virtual instruments, DAWs, sample libraries, notation programs, DJ software, etc. According to Music Trades, in the US the total retail value of recording/sequencing software in 2016 was $130MM. Compare that to $200MM in 2008; there's been a linear slide down since then.
 
According to the December 2016 report from Music Trades on the leading 225 global music industry suppliers, there aren't breakdowns for software vs. hardware - e.g., you can find out what PreSonus makes ($49 MM), but not specifically what Studio One brings in. I assume it's a relatively small part of that compared to their hardware.
 
You need to look at the bottom of the list to find the music companies...MOTU at $9MM (again, we don't know how much of that is DP and how much is interfaces), Waves at $12MM, IK at $16MM, Universal Audio at $23MM although I assume much of that is their hardware, etc.), and next is Ableton - one of the Big Guys at $25MM. The next biggest other than Avid (although there's no way to know how much of their $123MM is Pro Tools) is Native Instruments - a real anomaly at $74MM.