Citigroup has won formal approval from Saudi Arabia's Capital Market Authority to begin investment banking business there.
Citi was among the banks invited to pitch for roles in the stock market listing of Saudi oil company Aramco, in an initial public offering (IPO) that aims to raise $100 billion.
Saudi Aramco has also appointed Citi to lead a $2 billion financing backed by Britain, guaranteed by UK Export Finance, the British export credit agency.
Citi said last year that the bank wants to hire up to 20 bankers in Saudi Arabia to capitalise on investment banking opportunities that arise from the kingdom's economic reform programme.