Such requests are regular occurrences in cases involving white-collar crime, with similar delays taking place in the trials of Bernard Madoff and Norman Hsu.
Prosecutors initially had until today to return a grand jury indictment formally charging Galleon Group founder Rajaratnam and five of his co-accused conspirators, reports Bloomberg.
But a judge granted the US government more time to make its case.
The scandal has sent shockwaves throughout the financial world and led to two high-profile resignations.
IBM's vice-president for technology Robert Moffat was arrested alongside Rajaratnam and has left his post in order to concentrate on defending his name in court.
And Hector Ruiz, chairman of Globalfoundries, quit his job after being accused in media reports of passing on secret information regarding the formation of the company to the insider trading ring.
Despite not being charged with any offence, Mr Ruiz left his post earlier this month.
By Gary Cooper