OMAHA, Neb. (AP) — In the days before Berkshire Hathaway's annual meeting, classrooms and hotel meeting rooms around Omaha fill up with investors eager to learn more about the philosophy Warren Buffett used to build his fortune.

The outside conferences and gatherings are a big part of the draw for many who make the pilgrimage to Omaha because of the lessons learned and friendships nurtured.

But of course they remain much smaller than Saturday's main event, which is expected to again draw roughly 40,000 people to an arena where Buffett and Berkshire Vice Chairman Charlie Munger will spend hours answering questions — even though the meeting is now webcast live.

Financial author and analyst Laura Rittenhouse has been coming to Berkshire's annual meeting for 21 years in a row because it's reinvigorating to gather with so many other value investors, and she's made so many friendships.

"I would call it the mecca of value investing," Rittenhouse said.

So when Rittenhouse started talking with two Berkshire friends about starting an investment conference that focuses on gender equity issues in investing, they readily agreed that Omaha was the place to hold it. Rittenhouse hopes their event will encourage more women to join the investing business.

Investor Whitney Tilson used to attract a mix of seasoned professionals and amateur investors to his conferences around the Berkshire meetings. Tilson no longer holds the events, but he is looking forward to his 22nd annual meeting.

"There is really is nothing else like it. It draws people from all over the globe," Tilson said.

And the smaller conferences and gatherings of friends help enhance the attraction of Berkshire's meeting, Tilson added.

Author Bob Miles said it was natural to move his Value Investing Conference to Omaha from California in 2011 because the course already focused on Buffett, Munger and other prominent investors.

"Warren Buffett has popularized value investing and devotees from across the globe see the Berkshire weekend as a touchstone for honoring, learning and emulating an investment genius and masterful teacher," Miles said.

For Creighton University professor Gerald Jensen, setting up an investing conference at Creighton's campus just north of downtown made sense because of all the investors gathered before Berkshire's meeting.

"The characteristics of Buffett followers include: they are very interested in investing, and especially value investing; they have little to occupy their time before the meeting begins on Saturday; and many of them are concentrated in downtown Omaha," Jensen said. "Therefore, offering a value investing panel on the Creighton campus the evening before the Berkshire meeting is a logical move."

Heading into the weekend, both Jensen and Buffett were expecting packed houses at their events.