LONDON, Sept 9 (Reuters) - Whitbread, Segro and Rentokil Initial will enter the UK's FTSE 100 index later this month after a quarterly review, index compiler FTSE said on Wednesday.
The three are set to replace water utility Pennon Group, engineering firm Balfour Beatty and Foreign & Colonial Investment Trust.
In the review of the index, companies outside the FTSE 100 that grow to rank among the 90 largest by market capitalisation are automatically promoted, while the FTSE 100 firms with the lowest value or that fall to 111th spot or below drop into the FTSE Midcap 250 index.
The index changes will be implemented at the start of business on Monday, Sept. 21. (Reporting by Simon Falush; Editing by David Holmes)