Troubled Italian lender Banca Monte dei Paschi di Siena is struggling to sell fresh shares as part of its make-or-break plan to raise €5 billion ($5.19 billion) in new capital and avert a government bailout, according to a person familiar with the matter, as shares in the bank tumbled today.

The bank earlier this week launched a share sale and reopened an offer to bondholders to swap the junior debt they own into shares in a last-ditch attempt to replenish its capital buffers, as part of major balance sheet cleanup that includes the sale of €28 billion worth of bad loans.