There's something odd about the way insulin prices change

Insulin prices are rising — increases that mean some people are spending as much on monthly diabetes-related expenses as their mortgage payment.
But what makes the rise in insulin prices different than many other old drugs that have drawn scrutiny over prices, is that there is competition for insulin.
In most industries, competition drives down prices. In this case, the competitors appear to increase prices side-by-side — something that's been referred to as "shadow pricing."
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