Billionaire investor Carl Icahn has increased his stake in US natural and organic food group Hain Celestial.

Icahn and funds related to the activist investor now own just under 6.54bn shares in Hain, it was revealed in a filing with the Securities and Exchange Commission on Monday (29 November). Hain’s last quarterly filing showed Icahn held 5.04m shares.

The increase in the 74-year-old’s stake in Hain takes his shareholding to around 15% of the company’s outstanding common stock.

Icahn bought an almost 12% stake in Hain in May. He said at the time that he thought the company’s shares were undervalued.

In July, two directors were added to the Hain board under an agreement with Icahn. The agreement saw the investor back Hain’s slate of board nominees.

For the year to 30 June, Hain posted net income of $28.6m against a loss of $29.4m a year earlier. Sales, however, dropped from $1.12bn to $913.7m.

Last month, Hain president and CEO Irwin Simon said the company had made a “strong start” to its financial year, with profits and sales up 12%.