A gathering of hedge fund managers in Manhattan sends the share price on a wild ride.

Jeffrey Gundlach. Reuters

FORTUNE -- See on the chart at right where Apple's (AAPL) share price dropped to just over $540 shortly after 3 p.m. Wednesday?

That corresponds roughly to when the fund manager pictured above left, DoubleLine Capital's Jeffrey Gundlach, told a room packed with investment managers that he was shorting Apple. "I just wonder how many people will queue up around the block for an iPad 87," he said.

David Einhorn

See where the share price popped back up just before the closing bell? That happened after the next speaker, David Einhorn of Greenlight Capital, a hedge fund famous for taking very large short positions, said Grundlach was flat wrong. Apple won't lose its appeal if it stops making a new hit product every year. That "assumes that Apple is a hardware company. It's not," he said, according to the Wall Street Journal's account of the meeting. "Apple is a software company. Its value comes from iOS, the App Store, iTunes and iCloud."

According to Einhorn, hedge funds own only 5% of Apple's 935 million shares, as if to suggest that weren't enough to make a dent in the stock price.

But those funds are managed by guys who know a thing or two about leverage.

So if you are wondering who could have brought Apple's share price down more than $100 from its all-time high of $644 on April 9 to its low for the day of $541.04 -- carving $96 billion out of the company's market cap in the process -- you might start with the men who gathered Wednesday in Lincoln Center's Avery Fisher Hall for the Ira Sohn Conference to talk about the market and raise money for pediatric cancer research

Here's the list of the day's speakers, courtesy of ValueWalk:

• Bill Ackman, Pershing Square Capital
• Dwight Anderson, MP of Ospraie Management
• Dan Ariely, Professor, and expert in Behavioral finance
• David Einhorn, CEO of Greenlight Capital
• Jeffrey Gundlach, CEO of Doubleline, Bond Guru
• Jonathan Kolatch, CEO of Redwood Capital
• Philippe Laffont, PM of Coatue Management
• John Lykouretzos, PM of Hoplite
• Steve Mandel, CEO of Lone Pine Capital
• John Paulson, PM of Paulson & Co
• Larry Robbins,  CEO of Glenview Capital Management
• Kenneth Rogoff, Professor, Co-Author of Eight Centuries of Financial Folly
• John Wilder, Chairman of Bluescape Resources
• Meryl Witmer, GP at Eagle Capital Partners