I am following a service that shows the "percentage gainers" in real time, each morn for NASDAQ or NYSE. The data UNFORTUNATELY FOR ME, is based on yesterdays closing price, not the opening price. I waste time looking for "gainers" from the open (not the close). Does anyone know a data provider for such info? Oh yes, current data provider said they have to calculate from previous days close rather than opening price (which I don't believe is really required if they would just rewrite their software)
I don't think this is what you're interested in, but just in case:
AmiQuote will do it (for NYSE and NASDAQ only) in the form of a text file (so you'd have to do some simple programming) and is usually available at about 8 p.m. MST. I believe it comes with AmiBroker which is around $60 one-time.