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What: Shares of TTM Technologies (TTMI -0.14%) surged as much as 17% higher in Thursday's trading action, boosted by a strong second-quarter report.

So what: In the second quarter, TTM saw sales rising 35% year over year to $601.8 million. Adjusted earnings nearly doubled, landing at $0.28 per diluted share. The top-line figure was exactly in line with analyst expectations, but earnings came as a strongly positive surprise. Here, Wall Street would have settled for $0.18 per share, or hardly any annual growth at all.

Of course, year-over-year comparisons are tricky due to the game-changing merger with Viasystems, which closed halfway into the second quarter of 2015. The two companies entered the merger with trailing revenue streams of roughly equal size.

Now what: CEO Tom Edman pointed out that TTM's business mix shifted in unpredictable ways during the second quarter -- which isn't always a bad thing.

"A rebound in the cellular and communications end markets more than offset modest declines in the automotive and computing end markets," Edman said in a prepared statement. "Our aerospace and defense end market hit a quarterly record in revenues."

Looking ahead, TTM's management expects third-quarter sales of approximately $640 million and earnings near $0.33 per share. Hitting those targets would amount to a 2% year-over-year sales drop but 38% higher earnings for the quick-turn circuit board manufacturer.