What is the real-money, buy-side OMS market worth?

The buy-side OMS market is fragmented but it would be interesting to try and figure out what it's actually worth.  This is an attempt at that analysis.
Please note the following:
The market is not merely the value of the firms that have been sold, nor their revenue.

Not included in this analysis are:

  • Fees paid to third party firms for implementation and support services.
  • Fees paid to connectivity providers for bandwidth
  • Fees paid to hardware firms for switches, routers, firewalls, servers and storage to run these systems.
  • Cost of management time spent on project management and ongoing management costs
  • Platforms built in-house at asset management firms
  • Platforms provided to the buy-side as part of a larger system such as Bloomberg
  • Platforms that are constructed as part of a larger integrated solution and as such not reported as a distinct front office offering.
  • Private companies such as Charles River Development, Ullink and others
  • Firms with a predominant footprint in one market - such as IRESS
Noted acquisitions include:
[Update: FT states: £55m thinkFolio purchase in January.  Due to their paywall and CMS, you can find this by googling "Quick View: Markit outgrows its shareholders"]
A fascinating comment in the Economist about Aladdin:

"The $400m the company can expect in annual fees from outside users goes a long way to meeting the costs of the system and the nearly 2,000 employees who run it."

That comment suggests that the $400million in fees is not enough to actually cover the cost of the system - since it only goes a long way to meet the cost of the system. Something about these numbers suggests an interesting approach to product and project accounting within that organisation.

So - what's the OMS world worth?  Capitalised in terms of "what it would cost to buy the firms in the market" I'd suggest it's in the low single digit billions of GBP.  In revenue terms per year it's similar.  In profit? That's the big question...

[Update 23rd September 2015]

Factset acquire Portware for $265m