Alcoa Corp (NYSE:AA) had a strong afternoon as the company increased its guidance and posted an earnings beat in its latest quarterly report.

The company announced that for its first quarter, earnings impressed and guidance will top the mark due to an aluminum supply shortfall. The stock’s rating was increased by many analysts to a “buy” during the regular session in anticipation of the company’s quarterly report, as well as thanks to a six-year high in aluminum prices.

Alcoa said its earnings for the period rose about 22% to 77 cents per share compared to the year-ago quarter. Analysts were calling for the company to post an 11% gain in earnings to 70 cents per share.

The company also impressed on the revenue front as it raked in $3.09 billion in sales, marking a surge of 16.6% compared to the year-ago quarter. The Wall Street consensus estimate called for a 16% gain to $3.08 billion for the quarter.

For its fiscal year, Alcoa projects that its adjusted EBITDA excluding special items will be in the range of $3.5 billion to $3.7 billion. The figure is a considerable improvement from the company’s previous outlook, which came in January, and called for a full-year 2018 adjusted EBITDA in the range of $2.6 billion to $2.8 billion.

AA stock soared about 4% after the bell, following a 4.1% gain during regular trading hours Wednesday afternoon.