Euronet says it delivered a letter to the MoneyGram board of directors on 4th Deceember detailing its offer, which is valued at $20 per MoneyGram share, representing a premium of approximately 43% to the closing price of MoneyGram shares that day.

The letter says that Euronet would be willing to raise its offer "if the results of our due-diligence review would warrant it".

Euronet chairman and CEO Michael Brown says he is "disappointed" that MoneyGram has rejected the takeover approach.

"Your refusal to discuss with us the merits of our proposal is not in the best interest of your shareholders," says the letter. "We believe MoneyGram is an attractive business, and a combination with Euronet would create a powerful new player in the international money transfer business that would deliver substantial immediate and long-term value for the shareholders of both companies."

Brown says Euronet has enhanced its proposal to enable MoneyGram's shareholders to "participate even more substantially in the combined enterprise". Under the proposal, MoneyGram shareholders would own approximately 46% of the combined company.

The proposal would bring together the second and third largest global "send and receive" networks, says Euronext. However the combined company would still trail Western Union, which is reported to hold a 16% share of the money transfer market.

Minneapolis-based MoneyGram said in October that it had been badly burnt in the subprime mortgage crisis. Although its core business is money transfer MoneyGram recently ventured into mortgage-backed securities in a bid to increase returns, but the firm ended up writing down $230 million in the third quarter.

In the letter Euronet says is willing to make interim financing available to MoneyGram: "We have more than $250 million of cash in the bank, and additional funds available from our existing financing arrangements, and we are prepared to move quickly to put in place an interim financing arrangement if you so desire."

Read Euronet's letter here: