24-Hour Stock Trading Is Booming – and Wall Street Is Rattled

What fifteen minute delay? I'm pretty sure all of the retail brokers I have an account with (I have three, for historical reasons) give me instant (less network and computing latency) live data when I'm logged in.

Google/Yahoo give delayed data away to the public for free, but if you're actually trading, you have a broker and you won't wait fifteen minutes for data.

It's true that professional traders have less latency because they spend money on that, so they can act faster. But as a retail investor I really don't care if they pocket about a quarter of a cent per share on each trade I make, I'm happy there's liquidity and trading costs have never been lower for the little guy than in the present era.

Professional traders pay more for realtime data than non professionals. $10 a month or less will get undelayed data from most brokers

For example: https://nasdaqtrader.com/Trader.aspx?id=DPUSdata