Purpose: The main aims of this paper are to determine the extent to which experienced traders in investment banks based in London are learning by informal methods, which methods are to the fore, and whether HRD staff are providing support for informal learning. It also seeks to find evidence that such investment banks were attempting to become learning organisations. Design/methodology/approach: Empirical research was conducted involving in-depth semi-structured interviews with experienced traders, line managers of traders, and HRD professionals involved in the training of traders in London based investment banks. Findings: Most of the ongoing learning conducted by traders was informal, and on-the-job in nature. This informal learning was "ad hoc", poorly recorded, and limited in scope. Support of line managers to learning by their subordinate traders was patchy, with little accountability. HRD professionals were almost entirely concerned with organising formal training courses, and had little knowledge of, or involvement with, informal learning by traders. There was very little evidence of investment banks striving to become learning organisations. Research limitations/implications: The research study was limited to those investment banks willing to take part in the study, and by the banks selecting those to be interviewed. Practical implications: Investment banks have become a powerful component of the UK economy, and the ways in which their traders learn, or could learn, effectively in terms of competence improvement is key to the performance of these banks. Originality/value: Informal learning by traders in investment banks in the UK has been little researched to date. This paper addresses this inadequacy. (Contains 2 tables.)