Moon Phase is reporting that Ken Akamatsu will be announcing soon that he is going to end the Negima manga one year from now, almost 3 years ahead of schedule. It's cites that due to increasingly falling sales, 2 unsuccessful anime adaptations and pre-orders for the new OVAs not even reaching half of what they expected, that he has decided to bring the story to a close in 1 year. More details are to be given at a later date.
http://d.hatena.ne.jp/moonphase/20080614
http://d.hatena.ne.jp/moonphase/20080614