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What happened

Steelmaker AK Steel (AKS) closed trading down 10.4% on Thursday, rebounding only slightly after a sell-off that saw the stock down more than 11% at one point.

So what

Looking for someone to blame? Try Credit Suisse. On Thursday, the Swiss megabanker took an axe to its stock ratings for AK Steel -- and for U.S. Steel (X) and Steel Dynamics (STLD -0.62%) as well. According to the analyst, none of these three stocks is likely to "outperform" the market any longer, and all three are therefore downgraded to "neutral."

Why? As explained in a write-up on Thursday, Credit Suisse thinks prices on flat rolled steel have peaked. Demand has been "weak" all through H2 2016, and prices are likely to fall farther in the second half of 2017. Specifically, the analyst is predicting that prices of $625 per ton, which will be prevalent in Q1 2017, will fall to $535 per ton "by year-end."

Now what

This is not a popular view. To the contrary, many investors have been betting on a surge in infrastructure spending under a Trump administration buoying the steel sector. Combined with the potential for new tariffs on imported steel, this would send prices soaring.

But Credit Suisse challenges this thesis, predicting that "infrastructure stimulus [will] fail to produce any material benefits for US producers." Furthermore, warns Credit Suisse, "US HRC apparent consumption has been negative the past five months," and past tariffs haven't significantly cut the influx of imported steel, because "import penetration has remained relatively high by historical standards."

In short, with supply high and demand low -- and unlikely to grow despite Trump's election -- Credit Suisse sees cheap steel in our future, and stagnant stock prices for AK Steel, and for U.S. Steel and Steel Dynamics as well.