Pearson did not name the potential buyers.
People familiar with the matter said, however, that the group of families and staff and former staff that own the remaining 50 percent are talking to Pearson but need to raise cash to fund the deal.
Italian holding company Exor, the investment company of the Agnelli family and a major shareholder in Fiat Chrysler Automobiles, said later on Saturday it was in talks about raising its stake, which stands at 4.72 percent, according to its website.
Any increased investment in The Economist Group would represent a minority shareholding and there was no certainty a deal would be concluded, it said in a statement.
Fiat is a shareholder in RCS Mediagroup, which publishes newspaper Corriere della Sera.
As well as the Agnelli's, the owners of The Economist include other European dynasties such as the Cadbury, Rothschild and Schroder families.
Read MoreTeva to buy Allergan's generics biz
The co-owners of the weekly publication, which had a paid circulation of 1.6 million at the end of 2014 and reported 67 million pounds in annual operating profit in June, have greater voting rights than Pearson, which holds only B shares.
Any change of ownership would need the consent of the holders of the A shares, an analyst told Reuters on Friday.
It would also need to be approved by trustees who are tasked with preserving the independence of the ownership of the company and the editorial independence of the title.
The families were unlikely to back any plans by Pearson to sell to a third party, industry bankers said.
Bernstein analyst Claudio Aspesi estimated the stake could be worth 300 to 400 million pounds, based on a multiple of 15 times its net income of 46 million pounds.
It is unlikely that any offer would reflect the same rich multiple that Nikkei agreed to pay for the Financial Times.
The Japanese company had been in competition with Germany's Axel Springer to win control of the trophy asset.
Beside The Economist itself, the group operates several subsidiaries including The Economist Intelligence Unit, Economist Events and Economist Corporate Network.
A deal would likely take several weeks to be agreed, a source close to the situation said on Saturday.