Among the stock activity stories for Thursday, April 16, from AP Financial News: NEW YORK (AP) ¿ Shares of The9 Ltd. fell Thursday after the Shanghai-based online game operator said its license to operate the popular game "World of Warcraft" will be granted to a competitor after it expires. PITTSBURGH (AP) ¿ Shares of heavy equipment maker Caterpillar Inc. sank Thursday as an analyst downgraded the company's stock, citing possible losses in its finance unit and slumping demand for machinery and engines. NEW YORK (AP) ¿ Shares of genetic analysis company Illumina Inc. rose Thursday after the company said it sold 22 gene analyzing systems to the Broad Institute, boosting that institution's installed base to 47 units. NEW YORK (AP) ¿ Shares of Cougar Biotechnology Inc. fell Thursday after a Rodman & Renshaw analyst downgraded the stock, saying it is unlikely to advance for the rest of this year. NEW YORK (AP) ¿ Although near-term development prospects for one of its Florida properties are low, an analyst said Isle of Capri Casinos Inc. is among those likely to still be standing once an economic recovery occurs. NEW YORK (AP) ¿ Shares of StemCells Inc. jumped Thursday after the company said it signed a non-exclusive licensing deal with a major pharmaceutical company.