Dow Jones: The federal government is investigating a claim that solar-panel maker First Solar Inc.’s (FSLR) recent $400 million acquisition of a smaller rival wrongly included pending applications to use federal land. In early May, the U.S. Bureau of Land Management in Sacramento, Calif., received a citizen’s report claiming that OptiSolar Inc. of Hayward, Calif., had sold its land-use applications pending at the BLM to First Solar as part of the deal. The agency referred the matter to the …