What happened

True to their name, shares of Skyline Champion Corporation (SKY 1.20%) are airborne today, up 15.1% as of 11:45 a.m. EST after the company released a boffo fiscal Q3 2019 (no, that's not a typo; Skyline operates on a weird financial calendar) earnings report.

Expected to earn just $0.22 per share on $351.9 million in sales last quarter, the Elkhart, Ind., manufacturer of modular homes instead reported last night that pro forma Q3 earnings were $0.27 per share, and sales came in at $354.7 million -- ahead of estimates on both counts.

Check out the latest Skyline earnings call transcript.

Construction workers reading blueprints in front of a house.

Skyline has a plan for growing profits -- but is it too dependent on low taxes? Image source: Getty Images.

So what

Skyline's GAAP results weren't quite as strong as these pro-forma numbers suggest -- but they were still pretty good. Total homes sold increased 16%, and sales climbed more than 20% year over year. Thanks to a big decrease in income tax, Skyline's per-share profits leapt even higher -- up 73% to $0.19 per diluted share.

Now what

CEO Keith Anderson credited "merger synergies from [Skyline's] combined businesses" for the big increase in profits and predicted that production expansions in California and (especially) Louisiana "will help drive market share" in the coming quarters and years.

Investors seem to be taking those promises at face value, despite the CEO giving no specific guidance for future sales or earnings. Personally, though, I'm a bit leery, seeing how much of Skyline's earnings growth was owed to lower taxes, especially given the company's dramatic rise in costs -- cost of sales up 22% in the quarter, and selling, general, and administrative spending rising 48%, both far in excess of sales growth.

Investors enjoying big gains on their Skyline stock today might want to take these numbers to heart and get while the getting is good.