MADRID, July 24 (Reuters) - Spanish power utility Naturgy said on Monday its net profit increased 88% for the first half of the year, boosted by its liberalised business of energy management and supply operations.

Net profit for the period was 1.05 billion euros ($1.17 billion), up from 557 million euros a year earlier.

The company has recently signalled that rewarding shareholders will be a priority in the coming years, increasing its dividend floor through 2025 while trimming expected investment. It now targets profit of 1.8 billion euros in 2025.

Keeping shareholders happy will be essential at a time when the firm is mulling over changes that could completely reshape it.

($1 = 0.8986 euros) (Reporting by Pietro Lombardi, editing by Inti Landauro)