Whitbread boss Alison Brittain will be quizzed over the firm's plans for Costa Coffee next week when the group reports on first-quarter trading.

The coffee-shop-to-hotels firm said earlier this year that it will split the Costa chain and list it as a separate entity, following pressure from activist investor Elliott.

But it has since emerged that Costa is being circled by a clutch of private equity firms – including Bain Capital, CVC and TPG – opening the door to a potential £3bn sale of the high street chain.

The Press Association reported last month that Whitbread has been approached informally over a potential buyout of the firm, and investors will be keen to learn more alongside the firm's trading update.

Graham Spooner, investment research analyst at The Share Centre, said: 'The sales and revenues figures will most likely be overshadowed by the media and investors demanding to know more of the possible demerger of the Costa coffee business where management have suggested a possible separate share listing.

'However, it has been rumoured that several private equity vehicles have been interested and we'll wait to see if management have been lured.'

Costa, which Whitbread acquired in 1995 from founders Sergio and Bruno Costa, has more than 2,400 outlets and is embarking on overseas expansion.

It is thought that a private buyer would continue the expansion and tighten up costs at the group.

Premier Inn, which Whitbread also owns, will stay with the group.

Analysts also expect Costa to book a 2.3% fall in like-for-like sales in the first quarter, dragged down by woes affecting the British high street.

'The group gave a warning that the state of the UK high street would affect them despite the coffee chain seeing continued growth in the UK.

'Investors will also expect a progress report on their German expansion of their Premier Inn hotel chain,' Mr Spooner added.

At its full-year results in April, Whitbread reported annual sales growth of 6.1% to £3.3bn, while pre-tax profits rose 6.4% to £548m.

Annual figures also showed that Costa booked a 1.2% rise in like-for-like sales over the year, ahead of expectations.

City diary: The following events are due to take place next week:

Monday

No events scheduled

Tuesday

Finals: Carpetright

Trading updates: Petrofac

Wednesday

Trading updates: Bunzl, Whitbread

Thursday

Finals: BCA Marketplace, Greene King, Stagecoach

Trading updates: Tullow Oil, Wood Group

Friday

Trading updates: Reach, Serco

Office for National Statistics releases final estimate of first quarter GDP and current account figures