Shareholders and investment funds that make capital gains from Qatar National Bank's (QNB) bid for Cairo-based National Societe Generale Bank (NSGB) will face a 10 percent tax, Egypt's tax authority said on Tuesday.

Egypt's regulator approved the QNB offer in February after insisting that the Qatari lender buy 100 percent of Egypt's second-largest private sector bank by market value rather than the originally planned 77 percent stake.

QNB had said in December it planned to buy the 77 percent of NSGB held by its French parent Societe Generale.

The Egyptian tax authority said Societe Generale would be exempted from taxes for the transaction under an agreement to avoid double taxation between Egypt and France.

But individual shareholders and investment funds holding minority stakes in NSGB will have to pay a 10 percent tax on their gains, the tax authority wrote in a letter to the stock exchange, which was published on Tuesday.

QNB has offered 38.65 Egyptian pounds ($5.68) per NSGB share, compared with Monday's close of 38.49 pounds.

QNB is 50 percent owned by the Qatar Investment Authority, a sovereign wealth fund that has led the bulk of the gas-rich Gulf state's international acquisitions in recent years, including stakes in Barclays, carmaker Volkswagen and luxury store Harrods.