In regulatory filings, the Fondazione Monte dei Paschi di Siena, a charitable foundation with strong local political ties, said it had netted 43.7 million euros ($59.8 million) from the sale, which leaves it with 31.5 percent in the bank.
The stake was sold in January and in small tranches at prices between 0.179 euros and 0.189 euros a share. The stock closed at 0.183 euros a share on Friday.
The debt-laden foundation is looking to sell all or part of its large stake ahead of 3-billion-euro capital increase that Monte dei Paschi is due to carry out this year.
In December, the foundation forced the management led by Chairman Alessandro Profumo and CEO Fabrizio Viola to delay until mid-May or later the cash call, which had initially been scheduled for January.
By doing so, the foundation hopes to gain more time to sell its large stake and pay back debt.
Italian newspapers had cited a group of Italian banking foundations as possible buyers of part of the Fondazione Monte dei Paschi's stake in the bank, something all interested parties have denied.
Monte dei Paschi, the world's oldest bank still in business, needs to tap investors to repay 4.1 billion euros of state aid that it received after being hit by the sovereign debt crisis and a derivatives scandal.