A: In the case of ARUN, it will be reporting earnings after the August 26 close. I have noticed that stocks leave subtle and sometimes not so subtle price/volume clues on the day prior to the earnings announcement. That ARUN had good up volume today shows that there may be optimism about its upcoming earnings report, or better than that, information has been leaked that earnings are going to be a good surprise to the upside. Of course, this leak could just be a false rumor. But on balance, positive price/volume action in a stock just prior to earnings is often a good sign. Another explanation is that the high volume was reflect of support at the 50dma. Either way, I watch the price/volume action of the stock, assuming it is a leading stock, as ARUN's business and fundamental variables show. That earnings are being reported after tomorrow's close is a factor such that if I saw big downside volume, I wouldnt want to own the stock. But in this case, we are seeing decent upside volume.
More conservative investors may choose to avoid ARUN altogether or only invest in a half-position since earnings are being reported after tomorrow's close.