On Wednesday, the Reds rejected a bid of 100 million euros (£90m) from Barcelona for the 25-year-old.
Barca's second bid, which was rejected immediately, comprised an initial £76.8m plus £13.5m in add-ons.
In a statement on Friday, the club's owners Fenway Sports Group club said its "definitive stance" was that "no offers will be considered".
It added: "Philippe will remain a member of Liverpool Football Club when the summer window closes."
Speaking at a news conference previewing Saturday's Premier League match at Watford, manager Jurgen Klopp said Coutinho would miss the season opener with a back problem.
Klopp said he was also a doubt for Tuesday's Champions League play-off first leg at Hoffenheim as he had "not been in training since last Friday".
Coutinho, who scored 14 goals in all competitions last season, signed a new five-year deal in January that did not include a release clause. He joined Liverpool from Inter Milan for £8.5m in 2013.
Klopp said the Reds were not "a selling club" when Barca's previous £72m offer was rejected in July.
Barcelona have also had a bid rejected for Borussia Dortmund's 20-year-old forward Ousmane Dembele since they sold Brazil forward Neymar to Paris St-Germain for a world record £200m last week.
The German club confirmed they met Barca representatives but the offer did not meet their valuation of the France international.
