MILAN (AP) — Shares in Italy's most troubled bank, Monte dei Paschi di Siena, are down again amid rising concerns about its ability to remain solvent.

Shares were down 3 percent Tuesday though the bank said it had achieved one part of a turnaround program. Bondholders agreed to swap some 1.02 billion euros (1.09 billion dollars) in subordinated shares.

The future of Italy's third largest-lender is in doubt amid political turmoil, with Premier Matteo Renzi poised to resign after a stunning rebuke by voters to his constitutional reforms.

The timing of Italy's political crisis couldn't be worse for Monte dei Paschi, which is hoping to raise money through a stock offering as part of its restructuring.

The share swap announced Tuesday is part of that turnaround plan.