The JSE on Wednesday increased its offer for the Bond Exchange of South Africa (Besa) by 39% to R125 a share, up from the previous R90 a share.
The JSE in October announced its intention to acquire Besa for R173,3-million, but was criticised by Besa's biggest shareholder, the NZX, which said the offer was too low.
It announced in November that it was in discussions with the Besa board and could possibly increase its offer.
The JSE said in a statement on Wednesday that the offer consideration would be free from any downward price adjustments.
Further, the JSE would keep Besa's fee structure without increases for two years and would retain all staff.
The transaction had won the support of about 63% of Besa shareholders.