U.K. publishing and education company Pearson is locked in negotiations to sell its 50 percent stake in the Economist Group, which publishes the Economist, a weekly newsmagazine. The talks over a potential sale are with other group shareholders, according to a source close to the situation.

The news came in the same week that Pearson agreed to sell the Financial Times, Britain's leading financial-news publication, to Japan's Nikkei Group for about $1.3 billion to focus on its education business.

Pearson's stake in the Economist Group is believed to be worth about 400 million pounds ($620 million), according to reports in the Financial Times that cited two people close to the situation.

A company statement said, "Pearson confirms it is in discussions with the Economist Group board and trustees regarding the potential sale of our 50 percent share in the group." It also said there is "no certainty that this process will lead to a transaction."

Pearson acquired its stake in the Economist Group in 1957, alongside its purchase of the salmon-colored daily newspaper.

The Financial Times reported that any sale would have to be approved by the four trustees of the Economist Group: Baroness Virginia Bottomley, a Conservative former member of parliament; Lord O'Donnell, John Major's former press secretary; Tim Clark, deputy chairman of the consultancy G3; and Bryan Sanderson, an emeritus governor of the London School of Economics.

Among other shareholders of the Economist Group are the Agnelli, Cadbury and Rothschild families; the British asset-management company Schroder; and both former and current staff members.