In many investors' eyes, social media giant Facebook (Nasdaq: FB) has taken top prize for the worst IPO of all time. Yet even if you've already given up on the idea of ever owning Facebook shares, you need to prepare to be overruled if you own any funds or ETFs that track popular market benchmarks.

Earlier this year, just after Facebook had filed to go public and months before shares became available in its bungled IPO, I wrote an article pointing out that if it managed to sustain its likely opening-day market cap, it would just be a matter of time before it appeared in the S&P 500. That prediction hasn't come to pass just yet, but Facebook has taken its first step toward entering index-fund portfolios, and a more important position may come open for the stock in the near future.

Gunning for indexes
 Yesterday, Nasdaq OMX Group said that Facebook would join its Nasdaq Q-50 Index next week. That index is relatively obscure with only a small following among investors, but its main claim to fame is that its components are next in line to join the more popular Nasdaq 100 index when something happens to make its current constituents drop out.

Back in April, Nasdaq OMX Group changed the rules governing the Nasdaq 100 in a move that made it much more likely that Facebook could join the index sooner rather than later. The new rule allows a company to enter the index after being public for only three months, reducing the previous requirement of two years of public trading.

A direct move to the Nasdaq 100 apparently isn't going to happen, and a commentary in Barron's notes that the opportunity for Facebook to join the Nasdaq 100 this year has likely already come and gone. But with Netflix (Nasdaq: NFLX) having lost so much ground after taking on losses on its international operations and facing challenges to obtain content closer to home, it will probably fall out of the Nasdaq 100 at its next rebalancing, opening a spot that Facebook could potentially take down the road.

Other winners and losers
 Facebook wasn't the only company to make the Nasdaq Q-50, although it was by far the largest. NXP Semiconductors (Nasdaq: NXPI) will also be part of the index, thanks to its leadership in the rapidly growing near-field communications industry that many believe will be the key component of enabling smartphones to become mobile payment devices. In addition, Groupon (Nasdaq: GRPN) made the list, despite having plunged 80% since its opening-day price not quite a year ago.

Meanwhile, several companies got booted out to make room for Facebook and its peers. Interestingly, microblogging provider SINA (Nasdaq: SINA) was among the casualties, with its shares having lost more than half their value since early 2011. With Facebook mulling an entry into the Chinese market at some point if it can satisfy regulators there, it would arguably be poetic justice for Facebook to give SINA the fatal blow to its Nasdaq-100 hopes.

So much for value
 The sad thing about the Nasdaq move is that after a 50% drop in the stock, now might actually have been the perfect time for Facebook to get added to major indexes. Although more shares will likely come onto the market when the next lockup period expires, it's entirely possible that the lowest prices for Facebook are already behind us.

Nevertheless, with a market cap of more than $45 billion, Facebook is eventually going to make its way into pretty much every major market benchmark. The only question is when -- and whether smart investors will be able to anticipate its addition and profit from it.

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