• Exchange-traded notes are a risky debt security that allow investors to make leveraged trades on underlying assets such as stocks or bonds.
  • Clients have pulled around billions from Fisher Investments in recent weeks after the firm's founder made sexist comments at a conference.
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Billionaire Ken Fisher's investment firm has been slowly building a multi-billion dollar bet in a controversial part of the market.

Fisher Investment's has grown to control more than a quarter of the $22 billion market for exchange-traded notes, according to Bloomberg . ETNs are a risky debt securities that allow investors to make leveraged trades on underlying assets such as stocks or bonds.

The firm has partnered with banks such as Barclays and Credit Suisse to invest about $6.2 billion across 20 notes, Bloomberg reported . Fisher Investments is now the biggest stakeholder in five of the six largest ETNs and about 5% of the firm's $115 billion in assets are invested in the debt instrument, Bloomberg found.

Fisher senior vice president John Dillard told Bloomberg that recent client withdrawals won't impact its ETN holdings because the firm has added hundreds of new accounts and billions of dollars in assets in recent months.

"For the time we've utilized them, they have broadly added value to client portfolios," Dillard told Bloomberg in a statement, referring to ETNs.

Fisher has been under fire in recent weeks afterafter making comments at a conference that winning clients is like "trying to get into a girl's pants."

The remark sparked an exodus of capital from Fisher Investments. Clients have withdrawn almost $3.9 billion from the firm, according to Bloomberg .

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