This, according to a statement from indigenous rights advocacy group Bruno Manser Fund (BMF), has been confirmed by the Office of the Attorney-General in the Swiss capital, Bern.
The case against UBS was opened on Aug 29, 2012, following a criminal complaint by the NGO over the bank's close ties with Musa.
Musa and his nominees have been accused of laundering more than US$90 million in corruption proceeds from the tropical timber business through a number of UBS bank accounts in Hong Kong.
He also has a personal account with UBS in Zurich.
BMF is alleging that UBS failed to properly apply due diligence, as is required by Swiss law, when dealing with Politically Exposed Persons (PEP).
Musa is not only head of the Sabah state government but also the brother of the Malaysian Minister of Foreign Affairs, Anifah Aman.
The case is based on Switzerland's tough anti-money laundering legislation, which makes it a criminal offence for Swiss companies to be involved in laundering the proceeds from corruption and other crime in their worldwide activities.
'Kickbacks from timber concessions'
BMF claims that Musa has personally benefited from the large-scale logging in tropical rainforests in Sabah, one of the world's most biodiverse habitat, via kickbacks from timber concessions granted by the state.
London-based website Sarawak Report had earlier exposed how acres of pristine forest have been cleared under questionable concessions allegedly handed to Musa's brother, Anifah
Sarawak Report cited documents leaked from the Malaysian Anti-Corruption Commission (MACC) as its source.
UBS has so far remained silent on the allegations, as have the MACC and the Malaysian attorney-general.
However, Musa has denied Sarawak Report's claims, calling them ‘recycled' allegations.