Before revision:  We show how these drops and crises emerge as a natural result of local economical principles ruling tradesbetween economical agents and present evidence that heavy-tails of the return distributions are bounded by constraints associated with the topology of agent relations .
After revision:  We show how these drops and crises emerge as a natural result of local economical principles ruling tradesbetween economical agents and present evidence that heavy-tails , and the corresponding bounding exponent values can be derived .