Even the behind-the-scenes parts of the health care industry are dominated by a small handful of companies — and critics say that drives up prices for everyone.

Why it matters: The U.S. spends more than any other industrialized country for health care, largely because our prices are higher. And the monopolies that support those high prices could undermine both liberal and conservative dreams of a more efficient system.

The big picture: This is a trend that's happening at every level.

Hospital systems continue to merge with each other and gobble up doctors’ practices, which lets them charge more for the care they provide.

Insurers and pharmacy benefit managers are also merging, and are now on track to bring in more revenue than the tech industry's biggest powerhouses.

Yes, and: That trend toward concentration extends throughout the system, even into sectors that most patients never directly interact with, according to new data from the Open Markets Institute, shared first with Axios.

As long as we’re talking about hospitals, for example, let’s look at their suppliers: One company controls 64% of the market for syringes, according to OMI’s data. Just 3 companies control 86% of the market for IV solution. Two companies make 47% of hospital beds.

None of those sectors is particularly huge — syringes are the biggest, with $3.8 billion in annual revenue. But in a system that’s already not very competitive, each step without competition feeds into the next one.

“America’s health care crisis is brought you by monopoly,” Open Markets policy director Phil Longman said.

Dialysis is a particularly stark example:

Dialysis clinics bring in about $25 billion per year in revenue. And 2 companies — Fresenius and DaVita — control 92% of that market.

Fresenius is the leader, with almost 50% market share.

The manufacture of dialysis supplies is also concentrated around 2 companies — one of which is Fresenius. It controls 33% of that market.

This level of concentration can pose a problem for both liberal and conservative policy proposals, Longman argues.