Navios Maritime Holdings is sweetening the pot for preferred shareholders as it pushes forward with a tender offer that has been the centre of a lawsuit.

Fewer than half of the necessary shares were offered for swap by last Friday's deadline.

Now the Angeliki Frangou-led bulker owner has bumped its offer up on one series of preferred shares to $7.25 in cash per share or $8.28 in 9.75% notes. Holders of a second series are offered $7.16 per share in cash or $8.19 in notes.

The new offer is a more than a $2 increase over what company's initial proposal in December. Navios Holdings claims the new offer's cash amount represents a more than 110% premium on the preferred shares' market value.

The preferred shareholders have until 15 February to make a decision.

It is unclear whether or not the new offer is enough to placate the investors who sued to scuttle the offer two weeks ago.

They claimed the deal was an attempt to push them out so Frangou could issue a dividend to common holders.

The move would be a financial boon for Frangou, as she owns nearly a third of the company.

The initial deal offered either $4.83 or $4.77 in cash, depending on series, or $5.52 in notes per share — less than the alleged real value of either $6.66 or $6.56.

Tendering shares constituted a vote in favor of stripping preferred shares of their right to dividends.

Taken together, the shareholders earlier said they are being forced to take a bad deal or be left with nothing.

The shareholders' attorney, Mark Lebovitch of Bernstein, Litowitz, Berger & Grossman, was not immediately available for comment.

Lebovitch represented shareholders in a similar lawsuit in 2016.

At that time, Navios Holdings extended the offer twice. The second time the company removed the vote component and the shareholders declined to move forward with the lawsuit.

The plaintiff, Norman Roberts, moved to recover attorneys' fees, which the court denied.

New York-listed Navios Holdings has argued the result "completely vindicated" the company.