A credit union may purchase, sell, pledge, or discount or otherwise receive or dispose of, in whole or in part, any eligible obligations of its members and to purchase from any liquidating credit union notes made by individual members of the liquidating credit union as may be agreed upon by the board of directors of the liquidating credit union and the board of directors of the purchasing credit union, but no purchase may be made under authority of this section, if after that purchase, the aggregate of the unpaid balances of notes purchased under authority of this section would exceed five per cent of the capital of the credit union.