This is an interesting analysis by the Edge Singapore. They studied the Singapore Straits Times Index before and after the Singapore general elections.
Whenever the ruling party won by a significant margin, eg. in 1997, 2001 & 2015, the market rose the month following the elections. It should be noted that there were significant economic challenges in 1997 (Asian financial crisis) and 2001 (dot-com crisis). It appears that what the markets were seeking was a steady and stable government to bring it through the economic challenges. And when the ruling party won, the markets rallied.
What would it be like since Singapore is heading to the polls on 10 July? it certainly depends on who wins, by what margin and whether the market sees that as a sign stability for the economy. Check out this article below!