Questions about movement of funds from 1MDB came to widespread attention when the Wall Street Journal reported that in 2013 nearly $700 million had flowed from the debt-ridden fund to Malaysian Prime Minister Najib Razak's personal bank account.
Najib has repeatedly denied wrongdoing and, under pressure from the outcry caused by the report, said the funds were a private donation from a Middle Eastern country he declined to name. He has denied benefiting personally from the funds.
Malaysian Attorney General Mohamed Apandi Ali later said that Saudi Arabia's royal family gave Najib a $681 million gift, of which about $600 million was later returned. Apandi said that no criminal offense had been committed.
Singapore's investigations into 1MDB-related breaches started in March 2015. Since then, the MAS shut down two Swiss-based private banks, BSI and Falcon, and imposed financial penalties of 29.1 million Singapore dollars ($21 million) on eight banks including UBS and Standard Chartered.
The central bank also hauled several individuals to court and barred them from participating in the Singapore finance industry. The prohibition included a former director of Goldman Sachs Singapore, Tim Leissner, who issued an unauthorized letter to a financial institution based in Luxembourg to clear Malaysian tycoon Low Taek Jho of money laundering concerns.
MAS' managing director Ravi Menon said the two-year long review holds key lessons for Singapore.
"MAS has enhanced its AML (anti-money laundering) surveillance and taken unprecedented enforcement actions against errant institutions and individuals. Financial institutions have increased their risk awareness and strengthened their AML controls," he said.
"Our financial industry is in a better position today than it was when the abuses stemming from the 1MDB-related flows took place. The price for keeping our financial center clean as it grows in size and inter-connectedness is unstinting vigilance."