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What: Shares of truck-trailer manufacturer Wabash National (NYSE:WNC) were flying today, gaining 23%, after an impressive earnings report.

So what: Wabash had struggled of late, but the transportation specialist reassured investors today with adjusted earnings per share of $0.30, a solid turnaround from just $0.02 a year ago, and equal to analyst estimates. Revenue increased 21%, to $406 million, helped by its acquisition of Walker. CEO Dick Giromini credited the company's ability to "execute its strategic plan" for profitable growth and margin improvement, as margins were helped by growth in the Diversified Products segment, which increased four times with the Walker acquisition.

Now what: I had made a bullish CAPSCall on Wabash after its shares pulled back in its last earnings report. Shares looked undervalued, and the Walker acquisition looked ready to add to profits. After today's solid earnings report, the company still looks undervalued at a P/E of just 10, with strong growth ahead. Expect the stock to continue to climb from here.

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