David Sullivan said Grant had the full backing of the board despite the failed attempt earlier this week to replace him with Martin O’Neill.
Co-owner David Sullivan also said the manager will be given funds to strengthen his squad in what remains of the January transfer window.
“The entire board is 100 per cent behind Avram – he is a really decent person who deserves our support,” said Sullivan.
“We will do all we can to bring in players over the next 12 days and, once we have achieved that, we hope it will keep us up.”
West Ham remain in the hunt to sign Robbie Keane but they are also monitoring the situation of Hoffenheim striker Demba Ba, whose move to Stoke collapsed after he failed a medical.