The stock sell-off will be part of the fourth attempt to sell the company, one of Northern Europe's largest shippers.
Another 32 percent is being sold for privatization vouchers. That sale began earlier this month and closes March 22.
In addition to William de Broe and the stock exchange, the consortium will include the investment bank Suprema.
The 102 million shares will be offered to international investors for cash at a set price listed on the Riga bourse and possibly another stock exchange in Europe.
Under the agreement, the Riga bourse will be paid 50,000 pounds ($71,500) monthly for no longer than four months, 1.27 percent of the total amount raised by selling the 51 percent stake for cash to investors and a one-time payment of 100,000 pounds if the shipping company's shares are also listed on one of Europe's larger bourses by Sept. 1, 2002.
Together the firms will conduct an in-depth analysis of the company's legal and financial status and market the public offering, which could take place as early as June.
As part of the strategy the shares could also be listed on an international stock exchange, an issue that will be decided after potential investors are sized up.
William de Broe is part of the ING Group, one of Europe's leading investment banking firms.