According to the Financial Times, the financial institution originally reported it had lost $8.5 billion on investments with its own money in debt and equity during 2008.
However, new statistics published as part of a renewed commitment to fuller disclosure by the bank showed that the sum was $13.5 billion.
The additional $5 billion was not originally recorded as Goldman did not provide a full breakdown of its business activity and profits and losses made with its own money.
Despite this discrepancy in the statistics, the overall financial results for 2008 are not affected, the FT noted.
The revelation follows the publication of a report detailing the findings of an eight month investigation to review internal processes at the bank.
Goldman is expected to make 39 changes to procedures surrounding disclosure, transparency and client services as part of a bid to improve the public and investor perception of the bank.
It follows allegations by the Securities and Exchange Commission that the bank committed fraud in its selling of securities surrounding an investment product called ABACUS.
Goldman did not deny or admit to the charges but paid $550 million as settlement.
By Jim Ottewill