Big Data is when you have challenges that cannot be handled by traditional database systems.
Challenges in the context of Volume, Variety, Velocity, Veracity. These can be found in Financial Services.
This article looks at the Financial Services industry to examine Big Data and the technologies employed. It further covers ROI, Big Data analytics, regulation, governance, security, and storage as well as obstacles and challenges that have made the industry what it is today.
https://towardsdatascience.com/big-data-in-financial-services-f3d4fd7a30cd