In telecommunications as well as banking, you have enough data to reconstruct family relationships between clients. Based on data concerning card payments, phone calls, and location, you can correlate people in time and space. If you add some simple demographics, you end up with a surprisingly precise model that finds a person’s spouse, parents, siblings, etc. In some countries, this sort of data mining cannot be legally employed, but in others, regulations are not so strict. So, the bank can use this knowledge to improve a person’s risk score based on her family members, or a telecommunications operator can make a better targeted marketing offer.