Goldman Sachs, the Wall Street banking and wealth management firm, may lose its investment in a proprietary trading code and millions of dollars from increased competition if software allegedly stolen by a former employee gets into the wrong hands, a prosecutor said, according to media reports.

Sergey Aleynikov, an ex-Goldman Sachs computer programmer, was arrested 3 July after arriving at Liberty International Airport in Newark, New Jersey, US officials were reported to have said.

Mr Aleynikov, who has dual American and Russian citizenship, is charged in a criminal complaint with stealing the trading software. Teza Technologies, a Chicago-based firm co-founded by a former Citadel Investment Group trader, said it suspended Aleynikov, who started there on 2 July.

At a court appearance on 4 July in New York, assistant US attorney Joseph Facciponti told a federal judge that Mr Aleynikov’s alleged theft poses a risk to US markets.

Mr Aleynikov transferred the code, which is worth millions of dollars, to a computer server in Germany, and others may have had access to it, Mr Facciponti said, adding that New York-based Goldman Sachs may be harmed if the software is disseminated.