ZestFinance (former employee here) uses machine learning, I imagine Upstart does as well if they are talking about signals. There is a ton of data you can obtai

ZestFinance (former employee here) uses machine learning, I imagine Upstart does as well if they are talking about signals. There is a ton of data you can obtain about people from marketing and third party credit agencies, of course you mostly end up relying on your own ongoing loan portfolio performance to train and validate models as time goes on. Using ML for loan applications is an old idea. There is a whole chapter about credit scoring using decision trees, genetic algorithms, and neural networks in Miller's 1990 Computer-Aided Financial Analysis.