Mumbai: Borse Dubai has launched a $4-billion cash offer for Nordic exchange owner OMX, trumping US exchange Nasdaq's $3.7 billion bid, in a move that could force Nasdaq to make a higher counter offer. (See: Nasdaq's bid for Sweden's OMX faces Dubai challenge)

Borse Dubai's $3.96 billion takeover bid for OMX values the Swedish exchange at 230 crowns per share or 27.7 billion crowns ($3.98 billion).

The Dubai-based exchange had already acquired a 27.4 per cent stake in the Nordic exchange operator earlier this month. The offer price of 230 Swedish crowns represents a 14 per cent improvement on Nasdaq's offer of 208.1kr a share for OMX.

Borse Dubai, the owner of the Dubai stock exchange, said it would accelerate the Scandinavian stock exchange group's expansion in fast-growing markets.

The purchase would "provide members, issuers, institutional and retail investors with access to new opportunities in growth markets" and give "access to one of the largest liquidity pools in the world," Borse Dubai said.

The combination of the OMX and Borse Dubai would create the fifth largest exchange group in the world.

Borse Dubai, however, insisted that its acquisition of a near 30 per cent stake in OMX - achieved through purchasing actual shares and entering into option agreements - "did not constitute a public takeover offer."

The Swedish financial regulator, meanwhile, is probing the way in which Borse Dubai, run by former OMX chief executive Per Larsson, built its huge stake in OMX.

"This combination will establish OMX as the group's global platform, building on OMX's leading technology and strong brand to position it to become one of the fastest-growing major exchange networks in the world," Borse Dubai chairman Essa Kazim said.

OMX said it was studying the bid and would come back to shareholders shortly. Sources familiar with the matter said Borse Dubai had not yet secured OMX agreement.

Borse Dubai is a holding company for the Dubai government's stakes in Dubai Financial Market and the Dubai International Financial Exchange (DIFX).

OMX, in addition to owning and running exchanges in Sweden, Denmark, Finland, Iceland and the Baltic states, provides technology to about 60 exchanges worldwide, including the Australian Securities Exchange, Nordic power market Nordpool and the Singapore Exchange.