SIGMA is Goldman Sachs' smart order routing technology, which aggregates and provides access to various liquidity sources including Goldman Sachs' liquidity. The algorithms can be accessed via Goldman's multi-broker REDIPLus EMS or via major buy-side order management systems.

Within the suite of European algorithmic strategies, the SONAR algorithm, in particular, is designed to combine the benefits of algorithmic trading with the added feature of accessing dark liquidity. The algorithm works in two modes, 'stealth' and 'dark'. Under stealth mode, the algorithm seeks liquidity while avoiding signalling risk. Dark mode enables the algorithm to make either a portion or the entire balance of an order available for non-displayed crossing using SIGMA as a trader-defined benchmark. The Sonar algorithm is also live in the U.S. and benefits from accessing the SIGMA-X liquidity pool, which was cited by Tabb Group in September, 2007, as the largest dark liquidity pool in the US.

Peter Sheridan, Head of Goldman Sachs Algorithmic Trading in Europe said "With the introduction of MiFID and the rapid uptake of algorithmic trading in European markets, buy-side traders have stated that it has become increasingly difficult to locate liquidity in displayed markets. The SONAR algorithm helps European traders reduce information leakage to the market and improve their execution performance. It combines key benefits of algorithmic trading, automation and anonymity, with the ability to source 'block' liquidity in the SIGMA dark pool."