It was a roller coaster day for stocks, as investors continued to digest Donald Trump’s tax proposal against a backdrop of several key earnings reports. By the time the closing bell rang though, traders fizzled out. The S&P 500’s close of 2,388.77 was only 0.06% better than Wednesday’s last trade, leaving the index shy of the record-high mark of 2,400.98 hit in early March.

It could have been worse though. You could have owned Vale SA (ADR) (NYSE:VALE), Zimmer Biomet Holdings Inc (NYSE:ZBH) and American Airlines Group Inc (NASDAQ:AAL) as of Thursday’s open. All three all upended following alarming earnings news and/or equally alarming outlooks.

Here’s what investors need to know.

American Airlines Group Inc (AAL)

American Airlines may have done better than anyone expected it to last quarter. But, topping sales and earnings estimates was of little solace to AAL shareholders who saw earnings fall year-over-year, and who have good reason to be concerned about added expenses going forward.

For the quarter ending in March, American Airlines Group earned 61 cents per share on revenue of $9.62 billion. The pros were only looking for a top line of $9.62 billion, and a bottom line of only 57 cents per share of AAL stock. But, while revenues were up a bit on a year-over-year basis, income fell thanks to rising labor costs that may continue to rise.

On Wednesday, American Airlines announced it would be offering a 5% raise for flight attendants and an 8% raise for pilots, which will cost the company more than a billion dollars through 2018 and 2019. The added costs were enough to prompt a downgrade from J.P. Morgan, which lowered its opinion on AAL from “Overweight” to “Neutral” on concerns that such preemptive pay raises could become the new norm.

AAL ended the session lower by 5.2%.

Zimmer Biomet Holdings Inc (ZBH)

Like American Airlines, medical equipment maker Zimmer Biomet may have topped last quarter’s estimates, but concerns about the foreseeable future spooked ZBH into a 5.7% loss.

For its first fiscal quarter of 2017, Zimmer Biomet reported earnings of $2.13 per share versus estimates of only $2.11 per share of ZBH, and revenue of $1.98 billion versus estimates of $1.96 billion.

Still, the company scaled back its full-year outlook. Whereas Zimmer was looking for a top line of between $7.85 billion and $7.93 billion this year, now it’s only modeling revenue of between $7.83 and $7.91 billion. The earnings outlook was reduced too. Now the company is projecting 2017 earnings of between $8.50 and $8.60 per share of ZBH, versus prior guidance of between $8.50 and $8.68 per share.

Vale SA (ADR) (VALE)

Finally, Brazilian iron ore name Vale SA was hit hard today after posting its prior quarter’s earnings, though it was the company’s broad outlook for iron ore prices that may have done the bulk of Thursday’s damage.

For the company’s first fiscal quarter — end in March — of 2017, Vale drove revenue of $8.51 billion, up 72% from year-ago levels, but still falling short of expectations. Net income was also well up from the year-ago total of $1.77 billion, rolling in at $2.49 billion. But, that too fell short of the $3.25 billion some analysts were looking for.

The crux of the reason VALE fell 3.5% on Thursday, however, may have stemmed from its lackluster outlook for the iron market as a whole. Rather than the price near $80 per tonne the company had suggested was in the cards back in February, Vale’s head of ferrous minerals Peter Poppinga pared that price expectation to an average of $70 per tonne for 2017.

As of this writing, James Brumley did not hold a position in any of the aforementioned securities.