This paper investigates factors that influence trust and advice taking among retail investors when consulting with financial advisors and making real-world portfolio decisions. The data reveal that non-expert retail investors trust their advisors a lot. Trust formation appears to be well described by a simple heuristic that relies substantially on the advisor's communication style when deciding how much to trust and delegate investment decisions. Portfolio decisions appear to depend more on investors' perceptions about the investor–advisor relationship than on the risk and return characteristics of investments comprising the portfolio choice set. This evidence supports Pentland's (2008) “honest signals” as a more powerful mechanism underlying investor trust than standard metrics based on past performance. Trust and advice-taking heuristics can be interpreted as well adapted to the environment of the non-profit bank cooperatives in which they are observed, implying that trusting based on simple honest signals, although vulnerable to exploitation, can be interpreted as ecologically rational. Features of the investor's environment typical of non-profit cooperative banks imply that the heuristics investors use can perform rather well without requiring investment experience or financial sophistication, which most investors in our sample are well aware they lack.