By Elliot Gulliver-Needham Blackstone has upped its offer for Hipgnosis Songs Fund by $0.01 (less than a penny) in an attempt to sweeten the deal for shareholders in its takeover pursuit. Today, the American private equity giant raised its offer from $1.30 (102p) per share to $1.31 (103p) per share. The new offer valued Hipgnosis at $1.58bn (£1.27bn), an almost 60 per cent premium to its market value before the bidding began. The music rights company had been at the centre of a heated bidding war between Blackstone and Concord which ultimately led Concord to bow out last month. Concord said it…