Goldman Sachs Group Inc. delayed its first sale of samurai bonds in four years after Moody's Investors Service placed the bank under review for downgrade, according to a source.

Goldman Sachs pushed back the offering, which may have been as early as Friday, to at least Tuesday, the source said, asking not to be identified because the information is private. The brokerage told investors it plans to raise the size of the sale to at least ¥60 billion from ¥50 billion, and will widen the proposed yield premium, the source said.

The five-year sale will make it the busiest start to the year on record for the market for yen-denominated notes issued by overseas borrowers, according to data compiled by Bloomberg. A taxation rule change next month may make it more difficult for U.S. borrowers to sell samurai bonds. Moody's said Goldman Sachs' rating may be cut by two grades, which will lower it to A3, the seventh-highest level.