The twentieth century witnessed an extraordinary flow of institutional investment into urban infrastructure. Notwithstanding this, the demand for infrastructure projects exceeds supply of skills and capital. With this disconnect as a backdrop we develop a model of information flow to examine how financial assets are transacted over time and space. Specifically, we build on conceptualisations of “information content” from Clark and O'Connor () to propose a way of theorising “information density”. We apply this specifically to infrastructure investment and find four ways in which infrastructure investment is highly dense. This relates to asset-level definitions in infrastructure, opacity with respect to how products are securitised, high variance in investment performance, and high relational and investment expertise. We draw on a large qualitative sample of 53 in-depth interviews, which we validate with quantitative data, to support our findings.