In this paper we show that a part of the error in analyst forecasts can be traced back to reported segments, which do not report the full set of profitability components (assets, revenue or operating income). We also show that–against the common believe–disaggregation across business segments does not improve the ability of security analysts to forecast earnings. We attribute our findings to the design and quality of segment reporting under the “management approach” of both, ASC 280 (SFAS 131) and IFRS 8, which might direct the analysts focus. Our panel consists of a sample of 812 diversified US listed companies and covers the period 2009 to 2016.