Key TakeawaysArm Holdings has been added to the PHLX Semiconductor Sector Index.Arm ADRs have jumped some 150% in just over a year as a publicly traded company.CEO Rene Haas said the decision by the index underscored his firm's rapid growth. High-flying Arm Holdings (ARM) on Friday announced that it has been added to the PHLX Semiconductor Sector Index (SOX), effective today. American depositary receipts (ADRs) of the chip and software design firm have soared about 150% since it began trading on the Nasdaq ...