Notice anything?

They're all tech companies.

And their dominance is attracting attention from watchdog groups that say their market

power is harming competition and the economy.

Is it time to breakup big tech?

To answer that, you have to understand how tech has exploded.

For our purposes let's imagine the top 5 tech giants as Pacman, or "Pac-companies."

Except in this game, there are no ghosts around to avoid—no Blinky, no Clyde,

Those ghosts are U.S. regulators.

For the past decade, the U.S. has been mostly hands off with big tech companies, letting them become even bigger

by swallowing smaller rivals or entering new markets.

Bloomberg data show that in the last 10 years the big 5 have made close to 500 acquisitions

worth about $140 billion.

Because consumers like the companies' products, Amazon, Apple, Facebook, and Google

have developed huge market shares.

For example, Amazon receives about 93% of all e-book sales.

Google pulls in about 78% of internet search ad spending in the U.S.

Similarly, Apple and Facebook dominate in high-end smartphones and social media traffic.

But being a monopoly isn't illegal in the U.S... Or most other countries.

Regulators stopped equating big with bad a long time ago.

Monopoly cases brought by the U.S. have also dwindled.

In fact, the last high-profile case was filed in 1998, when the justice department successfully

challenged Microsoft's dominance of computer operating systems.

And that 20-year dry spell in monopoly cases has led some watchdogs to say that enforcement

in the U.S. has become too timid.

They say big tech is hurting innovation, jobs and wages,

and some even blame the behemoths for a decline in successful startups.

In Europe, America's big tech companies have faced more resistance with governments

more aggressively pursuing them.

For example, the E.U. has fined Google for abusing its market dominance and Germany is

investigating Facebook for its privacy practices.

Of course, the big tech players don't think they need to be broken up.

They argue their dominance isn't guaranteed because new competitors can easily

jump in.

As Google likes to point out, competition is just “one click away.”