Westend61 | Westend61 | Getty ImagesAMSTERDAM, Netherlands — Financial technology startup Nium told CNBC Wednesday it raised $50 million in new funds from investors, and is targeting an initial public offering in the next 18 months.The fundraising round was led by an undisclosed Southeast Asian sovereign wealth fund and backed by venture capital firms BOND, NewView Capital, and Tribe Capital.It places Nium's valuation at $1.4 billion. That marks a 30% discount to its previous valuation of $2 bil...