We are learning from Case Studies in Business Ethics by the late Rabbi Dr. Aaron Levine z"l professor of economics at Yeshiva University.
Disclosure and Reasonable Expectations in Speculative Transactions:
What constitutes reasonable expectations changes radically when one moves from sale of a consumer good to the sale of a speculative asset. Here, the reasonable expectation is that the entire transaction is made possible only because the seller (S) and the buyer (B) harbor variant and possibly even opposite expectations: B buys because he is convinced that the price will rise and S sells because he thinks it will fall.
Therefore, entry into this market place is accompanied by a warning to the reasonable man that he should research all publicly accessible information on which the trade will be made. If he ignores this warning in whole or in part, he is at his own risk.