Mr Sim, who has worked on deals including IBM's takeover of Lotus Development and the leveraged buyout of HCA, is currently in charge of M&A for the Americas region.
However, he is to step up to fill the global position vacated by Marc Granetz, who had combined the role with his activities as co-head of investment banking until October 2009.
Mr Sim's job as head of Americas M&A is to be taken by Andrew Lipsky, who is currently in charge of Credit Suisse's Americas diversified industrial and services team.
There is also a change in Europe where Giuseppe Monarchi is to take charge of M&A activity in the region, replacing David Livingstone, who is to become chief executive officer of Credit Suisse Australia.
Credit Suisse recently announced third quarter profits of $2.3 billion, thanks in part to an improved performance by its investment banking operation.
By Claire Archer