Manx Telecom says changing the date it releases this year's telephone book will mean it'll earn less from it than last year.
The company's issued a trading update about its interim results for the first six months of this year.
It says trading has been in line with expectations, with good performance in its core domestic business of fixed line, broadband, data and mobile.
And MT also adds it's seen continued growth in its Global Solutions arm, helping offset a fall in data centre business.