I don't think those things last very long, depends on what you run, but 10 minutes might be the max with a PC.
If it happens a lot, and you want an uninterruptible power supply, something that'll power a desktop, a good sized monitor, and your modem for the whole trading day if the power goes out big-time... this sounds a tad redneck I know, but you can build one yourself.
Here's less than $250, and it will easily last 10 hours.
Get a sealed (for indoor use) deep-cycle marine battery
https://tinyurl.com/y73k8j43
A decent 1500 Watt inverter
https://tinyurl.com/y8p2c746
And a small 12v car battery charger.
https://tinyurl.com/yblrfx6g
Put them out of the way, just plug your equipment into the inverter and keep the trickle charge on the battery.
That's an uninterruptible supply. It'll protect against any surges too in the event of a lightening strike or something.
If you don't care about having to re-boot your PC and then reloading your trading software if the power goes out, that takes a few minutes, you can just eliminate the battery charger and keep the inverter and the battery out in your garage. You're pretty quick fingered so that extra few minutes might matter to you. Either way, spend a couple hundred and you'll never have to worry.