Yahoo has really been upping its Android game with the acquisition of Aviate and the launch of apps like Yahoo Weather. Now the company has finally shown its finance app some love. Yahoo Finance has been completely rebuilt from the ground up with new features and a more modern UI. Frankly, I don't see as developers had any choice other than to start over—the previous app was incredibly outdated.
The new Yahoo Finance isn't Material Design, but it is more in-line with the Android aesthetics of today. There are three tabs that offer access to your personal stocks, news, markets, trends, and more. There are plenty of interactive graphs and you can choose to get push alerts for big swings in the market.
Almost anything would have been an improvement over the old version, which you can see a few screens of below. The only really odd thing about the updated app is that the hamburger menu seems to be used mainly to link to Yahoo's other apps. Otherwise, it's definitely one of the better financial apps in the Play Store.