I study a model of advisors with hidden motives: a seller discloses information about an object's value to a potential buyer, who doesn't know the object's value or how profitable the object's sale is to the seller (the seller's motives). I characterize optimal disclosure rules, used by the seller to steer sales from lower- to higher-profitability objects. I investigate the effects of a mandated transparency policy, which reveals the seller's motives to the buyer. I show that, by removing the seller's steering incentive, transparency can dissuade the seller from disclosing information about the object's value, and from acquiring that information in the first place. This result refines our understanding of effective regulation in advice markets, and links it to the commitment protocol in the advisor-advisee relation.