Singapore’s $50 banknote now carries the one triangle symbol on the reverse (below the word Arts). The signature on the new paper money has also been updated to that of Deputy Prime Minister Tharman Shanmugaratnam. This is the first denomination of banknotes to reflect his appointment as the new Chairman of the Monetary Authority of Singapore.
The first prefix for this variety is 4AA. Currently, other prefixes including 4AC, 4AD, 4AE, 4AF, 4AG, 4AJ, 4AL and 4AQ, 4AT and 4AU have been observed in circulation.
Update (12 July): Prefixes 4AH, 4AM, 4AR were spotted.
Update (14 July): Prefix 4AP was spotted.
Update (20 July): Prefixes 4AK, 4AS were spotted.
Update (25 July): Prefixes 4AA, 4AB were spotted; unseen prefix 4AN.
Update (10 August): Prefix 4AV was spotted.
The MAS $50 banknote has three different signatures to date, including that of Prime Minister Lee Hsien Loong (released in August 2004, 2AA) and Emeritus Senior Minister Goh Chok Tong (released in November 2009, 3AA). Both used to hold the position of Chairman MAS. Before the MAS issue, the Board of Commissioners of Currency Singapore (BCCS) has issued banknotes signed by Richard Hu (released in September 1999, 0AA; reprinted in 2011, 1AA to 1HF and 1JJ) and Lee Hsien Loong (released in 2002, 1HL to 1HZ and 1KA to 1KN).
MAS started issuing banknotes with symbols printed on the reverse since 2008 as an added security feature for their internal authentication. It has been understood that these symbols are used to indicate the print batch number for that particular denomination, and two of the future symbols will include the circle and star.
It is observed that two denominations printed during the same period may not have the same symbol. For example, the one triangle symbol is used on the $50 note (printed some time between 21 May 2011 and early July 2012) while the $10 banknote with one triangle was released in November 2010. The $2 note with one triangle was first spotted in circulation in February 2011.