A previous agreed acquisition by the generator, PowerGen, lapsed in November after the Government referred it to the Monopolies and Mergers Commission.
Bryan Townsend, chairman, said the move reflected Midlands' underlying strength and ability to go forward "in any eventuality", including as an independent company. He refused to comment on whether there have been approaches by other suitors since PowerGen's offer lapsed, but he added: "There are other options. Other things might happen. If a company bids for us we will have to put it to shareholders."
City analysts said that any future bid by PowerGen, should the MMC allow it, would now have to be higher than the previous pounds 10-a-share. One said: "This shows that Midlands is a good solid company and that PowerGen will have to come back with something more to gain control." The share price rose 34p to close at 965p.
The merger negotiations cost Midlands pounds 4.9m in the six months to 30 September. PowerGen still has almost 21 per cent of the company and will gain about pounds 40m from the special dividend.
Midlands' pre-tax profits fell to pounds 92.7m in the first half of the year from pounds 102.4m a year earlier, largely due to higher interest costs after a share buy-back and bid costs.
The interim dividend is up 31.7 per cent to 12.25p and the company has said that the full-year payout will be 37p, an increase of 24.4 per cent.
Midlands' gas subsidiary made an operating loss of pounds 1.3m in the six months because of the sharp fall in spot prices and the problems of over-supply in the market place.