Accountancy firm UHY Hacker Young announced it is handling the process with Peter Kubik and Andrew Andronikou – who were administrators of the side in 2010 – appointed as joint administrators once again.
Vladimir Antonov has resigned as chairman and director of the South Coast team.
Kubik confirmed: "We were appointed as administrators after uncertainty arose over the future of CSI. CSI has a number of sports-related assets and we are very confident of finding interested buyers for these subsidiaries.
"Our aim is to ensure that the sale process is as smooth as it possibly can be. We will now be undertaking a period of due diligence at CSI and once that has been completed we will be in a better position to answer questions.
"CSI own a number of sports teams, media franchises and entertainment rights businesses. None of CSI’s subsidiaries are subject to an administration order.”
Last week, Antonov appeared at City of Westminster Magistrates’ Court to fight extradition over an alleged £200m fraud at AB Bankas Snoras in Lithuania.
Prosecutors in Lithuania have issued a European arrest warrant for Antonov and co-Snoras shareholder Raimondas Baranauskas. The pair – who were arrested by City of London police on Thursday – are wanted for alleged fraud.
In a statement the club – nicknamed Pompey – insisted funding is in place for the short term, but is seeking alternative investment for its longer-term requirements.
Chief executive David Lampitt said: "After the extraordinary amount of work put in by so many people over the last 18 months to get to this point, it is incredibly disappointing for the club to find itself in this position.
"I want to assure staff and fans that we will continue to do everything possible to safeguard the position of the club and its longer term future."
In February 2010 Portsmouth FC became the first Premier League team ever to fall into administration.
It came less than two years after Pompey’s FA Cup triumph and impressive eighth-place finish in the top flight. The side – which suffered a nine point deduction – was relegated from the top flight that season.
By Andy Pearce