The existing literature on sell-side analysts demonstrates that not only analysts err in their forecasts, valuations and investment recommendations, but that they are also biased. Critically discuss the potential causes of errors and biases of sell-side analysts working at: (a) brokerage houses that do not offer any investment banking services to the companies covered by their analysts; (b) large investment banks that offer an entire spectrum of other services to the companies covered by their analysts; and (c) pure research firms that only offer analyst research services.