Next to making markets, Optiver is always looking for (statistical) arbitrage opportunities. Statistical arbitrage involves trading strategies that identify and try to capitalize on inefficient pricing of financial instruments, often characterized by temporary aberrations in the relationship between two financial instruments. Examples are the difference between the price of a share and a related depository receipt (e.g. an ADR) and the price of the DAX-index in relation to the EuroStoxx-index.
Usually this type of trading involves building up a long position in the undervalued instrument and a short position in the overvalued instrument. But more advanced statistical arbitrage can consider not just a pair of stocks, but actually tens or hundreds of stocks, in which some are bought and some are sold. By arbitraging out such tiny price differences Optiver contributes to the efficiency of the market.
Just as in market making activities the profit per trade is usually very small, so these strategies are usually implemented in automated fashion (using high frequency trading techniques), which enables us to employ such a strategy on a larger scale.