Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for receiving first voice data from a user, receiving behavior data associated with the user, and determining that the user is authentic at least partially based on voice recognition of the first voice data, and behavior analysis of the behavior data, and subsequently: prompting one or more spoken commands from the user, receiving second voice data representative of at least one spoken command of the user to trade at least one financial instrument, providing trade data for executing the trade of the at least one financial instrument, and determining that the trade data is valid at least partially based on the second voice data, and in response, initiating execution of the trade.