Banca Monte dei Paschi di Siena (BMPS.MI) said on Friday it had signed an underwriting agreement with a pool of banks to subscribe to the lender’s planned 3-billion-euro rights issue. The banks agreed to guarantee, severally but not jointly, the subscription of any shares not taken up in the issue after the offer of any unexercised rights, Monte Paschi said. AXA Group (AXAF.PA) and AXA Mutuelles have agreed to take up new shares in line with the stakes they currently in the bank, Monte Paschi said.