Lululemon is joining an exclusive club from Marketplace.

I'm Sabri Benashore, in for David Brunk Hachio.

Starting today, athleisure wearmaker Lululemon Athletica will debut on the S&P 500.

It will replace Activision Blizzard, because that was acquired by Microsoft, Marketplace

is Justin Ho, looks at what it means for a company to join the S&P 500.

There are plenty of perks that come with an S&P 500 membership card.

Being on the S&P 500 gives you more visibility.

That's Will Getzman, a finance professor at Yale.

He spent decades following what happens when companies join the S&P 500.

The Big perk is a slice of the more than five and a half trillion dollars

parked in mutual funds and ETFs that simply buy whatever's in the index.

When a company's added to something like the S&P 500,

a whole bunch of funds buy that firm, and then the price goes up.

That investment comes with some complications.

Drew Pascarella at Cornell University says companies prefer to be judged

on their individual performance, like how well Lululemon's mid-rise pants are selling.

But when a company joins an index, those factors can lose relevance.

There are institutional investors that are buying and selling an index,

not based on what Lululemon is doing, but based overall on macroeconomic factors.

That means big investors might start selling if they're worried about, say,

global economic growth, interest rates or consumer confidence.

As opposed to understanding that those macro factors might be more limited

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