This paper reports new experimental and survey data collected from bank customers at several Italian banks. These data aim to uncover the decision processes used by investors, including their investment goals, the information sets they consider, and the number of factors that actually influence high-stakes financial decisions. Most subjects use a strict subset of the information available to them, ignoring variables that standard economic models typically assume drive investors behavior. Rather than random trembling which would predict that omitted variables are dropped at random, fast and information-frugal heuristics appear to explain the information search and decision behavior of many subjects observed in this study, reflecting a lexicographic hierarchy of risk, time horizon and cost, in that order. A simple combination of a fast and frugal tree and a tallying rule predicts about 80% of investors decisions.