(Sharecast News) - General Motors shares were on the rise in pre-market trade on Tuesday after the Chevrolet, Buick, GMC and Cadillac manufacturer upgraded its full-year outlook on the back of a $500m tariff refund and a first-quarter earnings beat.

The auto giant now expects gross tariff costs to total $2.5bn-3.5bn in 2026, compared with an earlier estimate of $3.0-4.0bn, after the US Surpreme Court decision regarding certain US tariffs paid under the International Emergency Economic Powers Act.

As a result, full-year adjusted earnings before interest and tax estimates have been raised to $13.5bn-15.5bn from $13.0bn-15.0bn.

Even before the $500m refund, GM said that adjusted EBIT of $4.3bn for the first quarter, up 21.9% year-on-year, exceeded its own expectations. Adjusted earnings per share of $3.70 came in well ahead of the $2.60 expected by analysts.

"We have solid momentum in our core operations," said chief executive Mary Barra in a letter to shareholders.

"We maintained overall sales leadership in the U.S. and Canada. We led the U.S. industry in full-size pickup sales and share, with 42% of the market, and we were #1 in Fleet, including Commercial deliveries. In addition, we were #2 in EVs with growing market share, and #1 in Canada."

Revenues totalled $43.63bn over the three months to 31 March, down 0.9% on the year before, but still above the $43.51bn estimated by the market.

Stock futures were up 0.3% at $78.20 by 1309 BST.