CHICAGO/LONDON/ZURICH (Reuters) - A trio of billionaire siblings known for inheriting the privately-held packaging giant Tetra Laval have snapped up nearly 20 percent of International Flavors & Fragrances Inc IFF.N over two years, becoming the company's top shareholder, Reuters has learned.

FILE PHOTO: Kirsten Rausing is shown during the Tattersalls Musidora Stakes at York Racecourse in York, Britain, May 14, 2014. Mandatory Credit: Action Images/Julian Herbert/File Photo

Kirsten, Finn and Jorn Rausing - who control the Tetra Laval family food carton business that their grandfather founded - have quietly become top investors in IFF and other companies using an entity known as the Haldor Foundation in Liechtenstein, three people familiar with the matter said.

Filings show that Haldor controls a Singaporean shell fund called Winder Investment Pte Ltd, which since 2016 has amassed a $2.54 billion stake in IFF, the world’s second largest maker of scents and flavors.

There is no other publicly available information on Haldor because it is not listed commercially. The Liechtenstein Office of Justice said only authorized people could access information about the foundation.

A spokesman for the Rausing family confirmed that the three siblings were Haldor’s beneficiaries, and added the foundation’s investments are not connected to Tetra Laval. The spokesman declined to comment about Haldor’s investments in Winder or other consumer companies.

A spokesman for Tetra Pak declined to comment. International Flavors & Fragrances said it would not identify the people behind its biggest shareholder.

The mystery of who controls Winder Investment has kept IFF investors and analysts guessing for at least a year. The New York-based company, which sells scents and flavors that go into everything from perfumes and detergents to fizzy drinks and frozen meals, banked sales of $3.4 billion last year and dates back to the 1880s. A supplier to thousands of consumer companies, including Procter & Gamble Co PG.N, IFF in May announced plans to buy Israeli rival Frutarom for $7.1 billion.

Filings show that Winder took an 8 percent stake in IFF in October 2016, followed by at least 16 buying transactions since then. Over that time, shares of IFF have risen nearly 7 percent.

“At the beginning, everybody was scratching their heads wondering who they were,” a top-20 IFF investor told Reuters on Monday, adding that Winder’s increased interest in IFF had likely helped drive up the company’s share price.

The Rausing siblings’ fortune has roots in Sweden dating to the founding of the Tetra Pak packaging company, now part of Tetra Laval. Their grandfather Ruben devised a watertight cardboard container for storing milk, juice, ice-cream and yogurt that went into production in the early 1950s. His children turned the company into a multinational business empire.

Notoriously secretive about where they invest their wealth, the Rausings have been discreetly building positions in other consumer companies as well, one source said.

The Winder fund took a 6 percent stake in Switzerland's SIG Combibloc SIGNC.S, which listed last month, becoming its second-biggest shareholder. SIG ranks second in global food and drink carton packaging sales, behind the Rausings' Tetra Laval.

Another source familiar with the investment said the Rausings’ interest in SIG served as a hedge in case it begins to outstrip Tetra Laval in sales.

Through another Singapore-based fund called Tringle Investment Pte Ltd, the Haldor Foundation also holds the top stake in Comet Holding AG COTNE.S, which has helped a Tetra Laval unit build technology used by consumer goods companies.

Comet said Tringle had never behaved like an activist investor. Comet and SIG Combibloc declined to confirm that the Rausings are stakeholders.

SAFE, SECRET STOCKS

While shareholder activists have rocked the consumer industry in recent years, targeting major companies from Nestle SA NESN.S to P&G and Campbell Soup Co CPB.N, that is not the Rausings' intent at IFF, two sources familiar with the investments told Reuters.

Rather, they are investing their dividends from Tetra Laval in “fairly safe stocks” in the consumer products industry, which they understand.

Ingredient and packaging technology firms work closely with the biggest consumer goods companies in the world, and are considered safe stocks that could help the Rausings keep up-to-date on cutting-edge developments in the consumer industry. Billionaire Bill Gates is the largest shareholder in Givaudan SA GIVN.S, the world's biggest flavors and fragrances maker.

The sector has also been growing in recent years, as big consumer goods companies outsource parts of research and development to firms such as Givaudan and IFF in a bid to cut costs.

Michael Bender, who manages IFF’s investor relations, would not confirm or deny that Winder is controlled by the Rausings. But he said Winder was a long-term, passive investor.

“They ask questions about what’s going on in the quarter, what’s going on in strategy, our thoughts on M&A, our thoughts on capital allocation,” said Bender, referring to Winder.

“We have very honest discussions with them and talk to them very frequently. They’re very private, which is why it’s tough to find information on who they are...that’s just what they want to be.”

Beyond Tetra Laval and a handful of other companies and charities they are involved with, very little is known about Kirsten, Finn and Jorn Rausing.

In 2012, the family was thrust into the spotlight when the body of Eva Rausing - married to a cousin of Kirsten, Finn and Jorn - was found rotting at her home in London, having died from cocaine abuse two months prior. Another cousin, Sigrid, then wrote about the incident in a memoir titled “Mayhem.”