Navios Maritime Partners chief executive Angeliki Frangou has been snapping up shares in the diversified shipowner, and the move appears to be helping lift the stock’s price to the highest level since the end of 2015.

The Greek shipping magnate has spent a total of $10.5m on the New York-listed shares between 15 February and Monday, according to a TradeWinds analysis of data disclosed to the US Securities & Exchange Commission.

A filing by the Navios chief executive, who is also the company’s largest shareholder, shows she now holds a 16.7% stake in the company’s common shares, up from 15.6% at the time of her last filing.

Frangou owns the shares through a variety of private entities, with the largest chunk in the hands of affiliate N Shipmanagement Acquisition.

Her Olympos Maritime also owns 622,000 general partner shares, which equates to a 2% ownership interest in Navios Partners, an owner of container ships, tankers and bulkers.

Frangou could not be reached for comment for this story, but investors have reacted positively to the executive’s further investment in the company if its rising share price is any indication.

The revelation of the purchases helped fuel a significant rise in Navios Partners’ share price, which reached an eight-year high of $38.33 in mid-morning trading on the New York Stock Exchange.

The share price has gained nearly 17% since Tuesday’s closing price of $33.18.

Frangou quietly disclosed her plans to buy up Navios Partners shares last month in the notes of a securities filing.

“Ms Frangou intends, from time to time, to purchase, through one or more of her investment vehicles, common units, including in open market transactions, block trades or otherwise,” she said in the filing.

She said in the filing that the purchases would be funded by cash on hand in her various investment vehicles.

Frangou’s transaction comes as Navios Partners’ shares have been stubbornly cheap relative to the company’s net asset value.

Last month, Fearnleys Securities said it estimated Navios Partners’ NAV at $109 per share, meaning the latest share price remains at just 35% of that number.

When the shares were trading at $32 apiece, the investment bank estimated that amounted to just 29% of NAV, which it described as a “heavy” discount at the time.

Analysts Fredrik Dybwad and Oystein Vaagen lifted their 12-month price target at the time to $50 from $45.

Value Investor’s Edge found J Mintzmyer told TradeWinds that an insider buy of Navios shares makes sense given his estimate of Navios Partners’ NAV at $110 per share.

“Longer-term, I would prefer to see meaningful repurchases as this rapidly accrues value to all shareholders, especially if conducted at this absurdly cheap valuation,” he said.