We don't find an explicit condemnation of insider trading in the Bible either.
But, in this case, I recommend the parable of the Good Samaritan. We are our brother's keeper.
1. In the parable, the "brother" who needed "keeping" was not the predator who robbed the traveler and left him for dead on the side of the road; it was the traveler himself who had been set upon by the predator.
2. Among the various characters in this parable, the absence of any government authority in dealing with the problem is noteworthy. The whole point of the parable is that the Samaritan helped the man himself, and paid the inkeeper out of his own pocket for the man's care. He didn't bring him to the Caesar Augustus Trauma Unit at the Beth Israel Hospital and dump him in the emergency room.
I would also suggest that the underlying message of that parable really has nothing to do with the notion of "we are our brother's keeper." Instead, the parable is a direct statement about the formal termination of the Old Covenant; this is why the two people who passed by were deliberately described as representatives of the Old Law: first the priest, then the Levite (a special group of priests who had been selected to serve as special guardians of the Tabernacle). And the one guy who did his duty for his fellow man was a Samaritan, whose group was ostracized by the rest of the Jews.
The point of the parable is that the status of "brother" must be earned, and must be extended to anyone who has acted to earn it (by serving your needs).
We are our brother's keeper.
It takes a village.