GM's bright spot in disappointing earnings

General Motors' (GM) posted a rather disappointing earnings report today -- except for the results in sport utility vehicles, pickup trucks and crossovers, whose sales are booming thanks to an improving economy and lower gas prices.

During the first quarter, Chevrolet reported a 19 percent increase in crossover vehicle deliveries in the U.S. on the popularity of the recently launched Chevrolet Trax. The truck-making GMC unit notched a 15 percent gain, the division's best first-quarter performance since 2005 , bolstered by the popularity of the new Denali line of SUVs, pickups and crossovers. Demand remains strong for other GM models including the Cadillac Escalade and the GMC Yukon.

As sales rose on these profitable vehicles, so did GM's profit margins, which have gained for six straight quarters. More important, the automaker sold vehicles with lower incentives and at higher prices. Kelly Blue Book estimates that GM's average transaction price was $37,135 per vehicle, an increase of 7 percent from a year ago.

So, why did GM's stock get beat down by 3.3 percent, or $1.24, to close at $25.92 on Thursday? GM's profit of $945 million amounted to 56 cents per share, compared with only $125 million, or 6 cents per share, a year ago. But excluding one-time items, GM would have had earnings per share of 86 cents, which came up shy of Wall Street's expectations of 95 cents. First-quarter revenue fell nearly 5 percent to $35.7 billion because of currency effects and lower sales in South America and Russia.

All told, global sales rose only 2 percent for the quarter, and GM's U.S. passenger car sales fell almost 19 percent at just under 92,000.

Thank goodness for the pickups, SUVs and crossovers. "With gas prices still near a seven-year low point, and with credit more affordable and available than ever," Alec Gutierrez, a senior analyst with Kelly Blue Book told CBS MoneyWatch, "GM, like the rest of the industry, has seen a significant increase in sales of their most profitable vehicles, namely Silverado, Sierra, Escalade, Suburban and their other sport utilities."

Indeed, the Chevrolet Silverado pickup gained 18 percent in transaction prices, as did the Chevrolet Equinox SUV, and Cadillac Escalade soared 13 percent, according to Kelly Blue Book. GMC racked up a 6 percent increase in average transaction prices overall.

However, weakness in overseas markets overshadowed some of the strength in the U.S. and GM's core North American market, where it earned $2.18 billion.

"While profit growth is mostly fueled by the U.S. and surrounding markets, investment is taking place heavily overseas, though GM did undergo a stock buyback," Akshay Anand, analyst for Kelley Blue Book, told CBSMoneyWatch. "An earnings hit or miss likely will come down to recall charges and foreign exchange as the dollar continues to strengthen. However, for now, GM is well positioned in the market as it continues to reinvent itself."

GM's share in the SUV and pickup market is about 18 percent, ahead of Ford's (F) 15 percent and Fiat Chrysler's (FCUA) 11 percent, according to TrueCar Executive Vice President Larry Dominique. Domestic manufacturers have an advantage over their foreign counterparts in the current market because they offer broader lineups.

GM can't afford to set the cruise control. Ford, which Dominique says "has done a great job in keeping incentives low," is ramping up its production on its redesigned F-150 pickup trucks, while Nissan (NSANY) is eager to boost its market share from 8 percent to 10 percent, he said.

Dominique also sees competitive pressure coming from Chrysler's Jeep line, which he says "has been a great performer and volume contributor to Chrysler."