Shares of American Airlines plunged 7.76% during intraday trading on Thursday, hitting a six-week low after the carrier slashed its full-year profit outlook and projected a surprise third-quarter loss, shaken by the relentless rise in jet fuel prices.

The sell-off was triggered by the company’s revised guidance. American now expects full-year adjusted earnings per share to range between a loss of $0.65 and a profit of $0.65, a sharp downgrade from its earlier forecast of a loss of $0.40 to a profit of $1.10. For the third quarter, the airline anticipates an adjusted loss of $0.70 to $0.10 per share, missing Wall Street’s consensus estimate of a $0.28 profit. The grim outlook overshadowed a second-quarter revenue beat and record quarterly sales, as management pointed to a $6 billion year-over-year headwind from higher jet fuel expenses.

The renewed spike in fuel costs—driven by escalating U.S.-Iran tensions and disrupted traffic through the Strait of Hormuz—has added billions to the carrier’s expense forecast. American disclosed that based on the forward fuel curve as of July 21, its third-quarter fuel bill would be $1.7 billion higher than previously anticipated, with costs surging by over $700 million just since the start of July. While strong travel demand and higher fares helped offset nearly half of the $2.2 billion year-over-year fuel expense increase in the second quarter, the ongoing fuel volatility has clouded the near-term earnings picture, prompting management to warn of continued price swings.