Without delving into currency fluctuations, retaliation from foreign trading partners, crony capitalism, etc., one way to handicap who the winners and losers of the taxing of imports by 20% would be is to simply look at the players who are for and against it.
Keep in mind, the U.S. -- with two-thirds of its GDP owing to consumer spending -- is a resoundingly consumer-driven economy.
Here's what Americans for Affordable Products (a coalition of 120 retailers [make their money via the consumer], which includes the likes of Best Buy, Dollar General, Macy's, Rite Aid and Walmart) think of the proposal:
We oppose any border adjustment tax (BAT) because it will increase the cost of clothing, food, medicine, gas, and other essential items that Americans rely on," the group says on its website. "Consumers shouldn’t bear the burden of this new tax while some corporations get a tax break.And here's from a Knowledge at Wharton interview with Wharton's own Ann Harrison and Penn Law's Michael Knoll:
... big exporters, including technology companies and large industrial companies like General Electric could have nil or even negative tax liability, he said. Indeed the chief executives from 16 companies, including GE, Oracle and Pfizer, sent a letter to congressional leaders this week in support of the GOP tax plan.