Jump bidding is common phenomenon in some auctions. It means that a bidder increases the price by more than the minimum required level. I propose an econometric model to explain jump bidding in auctions. The data used are from e-Bay and concern different products.

We build a subgame perfect Nash equilibrium of a common property productive asset oligopoly. We derive two surprising results. First, the steady state level of asset can be a decreasing function of the asset’s implicit growth rate. This phenomenon arises when the initial stock of asset is below a certain threshold. It represents a double curse for a common property productive asset where the well-known tragedy of the commons due to a lack of property rights is exacerbated by an increase in the productivity of the asset. Second, we show that a reduction in the number of firms exploiting the asset can, in the short run, result in an increase of the industry’s exploitation and a decrease of the level of the asset’s stock.

The Internet increases ways firms can reach consumers. One of them is to send emails to consumers. These commercial emails or spams seem to have the advantage of being an almost free medium to reach consumers. I first consider an infinite horizon optimization problem where the spammer has to make a decision upon the number of spams to send in a continuous time setting. Then I extend this initial framework in order to take into account the case where there is a finite number of spammers each of them "poluting" email-boxes with spams in order to get some of consumers' attention. I characterize the optimal spamming strategies as Feedback Nash Equilibrium when spammers are symetric and where the stock of total emails sent and consumers' attention define the state of the system. I derived afterward managerial implications.