"I believe that the markets have already taken under consideration the possible volatility and all the risks are taken into account. So I do not see any more risks," Ulyukayev said.
According to him, no sharp drop in oil prices or the ruble value should be expected to follow a possible Brexit, although "no one will tell you exactly [what the Brexit influence might be], it is impossible to assess that."
"Firstly, if this [Brexit] happens, the process itself will be delayed for many years, for a long period. Secondly, there can be different forms of relationship between the remaining 27 countries and the country that leaves. It is very difficult to imagine the final configuration of it all. And from it, of course, everything else will depend to a great extent," Ulyukayev noted.
However, he expects that voters in the United Kingdom will choose to stay in the European Union.
Ulyukaev said that he believed that "supporters of UK stay in the EU will win with a little difference."
On Thursday, the British public are voting on a referendum on whether their country should stay in or leave the European Union. The referendum was scheduled after UK Prime Minister David Cameron and the leaders of the 27 EU member states agreed in February to grant the United Kingdom a special status within the bloc.