http://news.bbc.co.uk/2/hi/business/4205019.stmTraders at US banking giant Citigroup are facing a criminal investigation in Germany over a controversial bond deal.
The deal saw the sale of 11bn euros ($14.4bn; £7.6bn) of government bonds in a few minutes on 2 August, with 4bn euros-worth then bought back later.
The move was widely criticised at the time, and now the German regulator has said it has found evidence of possible market manipulation.
Citigroup said it would continue to co-operate fully with the authorities.
"We are disappointed that the BaFin has referred to the prosecutor the question of whether action should be brought against individuals involved," Citigroup said.
If the traders are found guilty, they could face a five-year jail term or a fine, Reuters reported BaFin as saying.