Ford to build plant in MexicoDETROIT — Ford plans to build a new $1.6 billion auto assembly plant in Mexico, creating about 2,800 jobs and shifting small-car production from the U.S. at a time when moving jobs south of the border has become a major issue in the U.S. presidential campaign.The company announced the plant in the San Luis Potosi state Tuesday without saying specifically what cars it will build there. But the United Auto Workers union has said Ford plans to shift production of the Focus compact and C-Max small gas-electric hybrid from suburban Detroit to Mexico, where the cars can be made at lower cost and more profitably.The UAW’s new four-year contract with Ford, signed last year, guarantees new vehicles for the Wayne, Mich., assembly plant and a $700 million investment that preserves the plant’s 3,924 jobs. Union members have said they expect the factory to get a new version of the Ranger pickup and a new Bronco small SUV.

New rules cast doubt on mergerDrugmakers Pfizer and Allergan are scrambling to determine whether to proceed with their plan to merge and move Pfizer’s address — but not its operations or headquarters — to lower-tax Ireland. They are taking another look after the U.S. Treasury Department issued new rules to make such “tax inversion” deals less profitable.Analysts and tax experts are debating whether the new, unexpectedly aggressive tax law changes issued late Monday will kill the deal.Numbers say hiring up in FebruaryWASHINGTON — U.S. hiring jumped to a nine-year high in February, a sign of robust business demand for new workers, while the number of open positions slipped.The Labor Department reported Tuesday that 5.4 million people found jobs, a 5.8 percent jump from January and the most since November 2006. More Americans also quit their jobs. Both figures point to a healthier, more dynamic labor market.