Tesla Inc. on Monday became the largest U.S. auto maker by market value, Tesla stock climbed as much as 3.7 percent in early Monday trading, boosting its market capitalization to $51 billion. GM is valued at $50.30 billion. Tesla announced that it produced 25,418 electric cars in this year’s first quarter. The company, run by Elon Musk, will start producing its new, more affordable sedan, the Model 3 later this year. The Model 3 is expected to transform the niche electric car company into a mass-market manufacturer.