The winds of change are blowing through the S&P 500 -- and traders are already taking advantage of the new climate.

The widely aped S&P 500 announced changes to its components yesterday. In order to reflect their growing market caps, F5 Networks (Nasdaq: FFIV), Netflix (Nasdaq: NFLX), and Newfield Exploration (NYSE: NFX) will move from S&P's MidCap 400 index to the S&P 500.

In turn, current S&P 500 members New York Times Co. (NYSE: NYT), Office Depot (NYSE: ODP), and Eastman Kodak (NYSE: EK) will fall back into the MidCap 400. In addition, Cablevision (NYSE: CVC) will take the place of King Pharmaceuticals.

King is being nixed because Pfizer is about to acquire it, but the other three are simply victims of their fade in popularity. Newspapers, office supplies, and photofinishing are industries that have come under fire in recent years, though Office Depot's slide is more company-specific.

Over the next few days you'll be seeing an interesting phenomenon take place. Cablevision, F5, Netflix, and Newfield won't be officially added to the index until the end of next week, but that's unlikely to stop the next few days of gains. Investors know that index funds managers will be buying to be in position by next Friday's close, so buying in ahead of the horde is an easy trade.

It doesn't always play out that way. If speculators outnumber the eventual fund investors, the gains being notched today by the four additions may come undone in the coming days.

The move is redemptive at an opportune time. After all, Cablevision continues to shed cable subscribers, a problem that isn't going to get any better after it shut out couch potatoes during the World Series in a contract dispute. Netflix took a hit earlier this week when its CFO announced that he was leaving the company.

Over the next few days, all will be forgiven. The four inductees can't coast, though. There's nothing stopping Standard & Poor's from turning to them the next time it needs to weed out laggards to make room for next year's hot additions.

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Longtime Fool contributor Rick Munarriz has never been added to an index fund. He does not own shares in any of the stocks in this story, except for Netflix. He is also part of the Rule Breakers newsletter research team, seeking out tomorrow's ultimate growth stocks a day early. The Fool has a disclosure policy.