Nasdaq OMX Group agreed to acquire index provider and analytics group Dorsey, Wright & Associates for $225 million, as the exchange operator expands its exchange-traded fund and so-called smart-beta indexing segments to diversify its business.

The deal, which will be funded with a combination of cash on hand and debt, will make Nasdaq's global indexes segment one of the largest providers of the fast-growing smart-beta indexes. Unlike traditional market capitalisation weighted indexes, smart-beta shifts the index weightings based on certain factors.