Private-equity firm Kohlberg Kravis Roberts has remained coy on speculation that it could be preparing a bid for US organic food retailer Whole Foods Market.

KKR and fellow private-equity firm Bain Capital may be lining up a cash offer of US$90 a share, according to a report in the UK's Daily Mail.

According to the newspaper, a potential deal would value Whole Foods at around US$6bn.

In late July, Whole Foods upped its full-year earnings target after third-quarter profits jumped 35% to US$88.5m.

It is forecasting diluted earnings per share to be US$1.91-1.92, up from its earlier forecast of $1.87-1.90.

A spokesperson for KKR declined to comment on the speculation, while Bain Capital has not yet responded to requests for comment.

Shares in the company were up 0.66% today (19 August) to US$59.23 a share at 10:31 ET.