The UK's Competition Commission is delaying the publication of its final report on the two existing takeover bids for the London Stock Exchange by eight weeks.
The watchdog had planned to publish its report on whether plans by Deutsche Börse and Euronext to acquire the LSE would be anti-competitive on 12 September, but says it will need more time due to the "exceptional complexity" of the investigation.
The new deadline for publication of the report is 7th November.
In July the watchdog said a takeover of LSE by either Deutsche Börse or Euronext would harm competition by requiring customers to use their respective clearing services. Deutsche Börse owns clearing services provider Eurex Clearing, while Euronext is the biggest shareholder in LCH Clearnet, the current clearing services provider for the LSE.
Earlier this week Australia's Macquarie Bank said it was considering making a cash bid for the LSE as part of a consortium.