What's the world's largest security firm?

I was under the impression that G4S was the world's largest security company, but apparently there's more than one contender for that title. If you google it, ADT actually comes up first (well, for me. It's hard to know what your personalized google results will deliver), but then there's a bunch of G4S references. I think ADT is the biggest electronic security company, and G4S has the most employees. So, imagine my surprise when I saw this press release come across my desk -
The World's Largest Security Firm Makes Final Preparations for the Vancouver 2010 Olympic Winter Games
- and it wasn't referring to G4S:
NORTHRIDGE, Calif., Feb. 10 /PRNewswire/ -- The greatly anticipated Vancouver 2010 Olympic Opening Ceremony is set to kick off the Games this Friday at BC Place Stadium and final preparations are underway. Contemporary Security Canada (CSC), an affiliate of the world's largest security firm, Contemporary Services Corporation, was awarded the contract to provide the security screening services for the Games early last year. With the Games just a few days away, CSC is ready with its 5,000 member highly-trained workforce, which will be responsible for maintaining the safety and security of the Games' guests and participants at the 27 competition and non-competition venues across Vancouver and Whistler.
Bolding is mine, obviously. Really, though? Are they the largest and I've just not been paying attention? Apparently:
Led by Founder and CEO, Damon Zumwalt, Contemporary Services Corporation and its affiliates are the world leaders in event staffing, crowd management, security, and guest services for both the entertainment and sporting event industries. CSC's 42 years of experience have resulted in a loyal and esteemed client base, including more than 100 stadiums and arenas, over 70 universities and colleges, more than 20 convention centers, and numerous clients in the MLB, MLS, NBA, NFL, NHL, and NASCAR. CSC also has experience providing services to the world's largest special events, including the U.S. Open, 29 Super Bowls, 7 Olympic Games, 4 Presidential Inaugurations, and 2 World Cups.
Those numbers actually aren't that impressive, though, for the "world's largest security firm." 100 stadiums and arenas? 70 colleges and universities? Pfft. Aren't there 70 colleges and universities in Boston alone? That doesn't sound like largest in the world to me. Can you just go around calling yourself the world's largest security firm without actually being the world's largest? Or are they, in fact, bigger than Securitas and G4S and ADT? Perhaps I should actually find out the answer to this question, but I'm kind of busy today...


Hmmm... their "5,000 member highly-trained workforce" amounts to just 1% of that of G4S.

Perhaps they are being so well paid by the Canadian government that they will be the largest security company in the world AFTER the Olympics ?

Did you know that Provident Security Corp. is the world's largest security firm owned by Mike Jagger?

Also, you might not be aware that my son recently built the World's largest Lego tow-truck that's ever been in our living room.

There must be some fine print missing somewhere. 

[...] course, G4S is a mighty big animal (the biggest according to some, though not the biggest according to others…) with somewhere north of 580,000 employees in over 110 countries, so I was looking around [...]

If you read the excerpt you posted, you'll notice that CSC is an 'affiliate' of "the world's largest security firm", which is G4S.

So CSC is not the largest; rather, they're an affiliate of the largest.