LONDON (Reuters) - British luxury brand Mulberry on Tuesday rejected a second takeover proposal from Mike Ashley's Frasers Group, calling it "untenable".

Frasers on Oct. 11 had raised its proposal to 150 pence per Mulberry share, valuing the brand, best known for its handbags, at 111 million pounds ($144 million).

Mulberry's biggest shareholder, Challice Limited, the vehicle of Singapore-based property tycoon Ong Beng Seng and his wife Christina which owns 56.4%, said on Oct. 13 that it would not support Frasers' proposal.

Under UK takeover rules, Frasers, which owns 37% of Mulberry, has until Oct. 28 to make a firm offer or walk away.

Shares in Mulberry closed Monday at 125 pence.

($1 = 0.7689 pounds)

(Reporting by James Davey; editing by Sarah Young and Jason Neely)