Facebook 今年12月就会加入 Nasdaq-100 index http://online.wsj.com/article/SB1000087239639044423310457759557 Investors hoping that index funds will give Facebook Inc.'s FB +0.13% battered shares a lift could be in for a long wait. When the Nasdaq Stock Market decided in April to shorten the "seasoning" period for any stock to three months from as little as a year, it made the social-networking company, which went public in May, eligible for inclusion in its Nasdaq-100 index as soon as Sept. 1. Changes to indexes, known as "rebalancing," are closely followed by traders, as additions mean that mutual funds and exchange-traded funds that explicitly replicate them are forced to buy the stock, regardless of its performance. Many funds that are benchmarked against an index buy as well. But any uplift from joining the Nasdaq-100, which includes Internet and technology giants such as Apple Inc., AAPL -3.60% Google Inc. GOOG -1.90% and Baidu Inc., BIDU -0.71% is likely to be months away. Although Facebook's stock-market value, at $52 billion, should easily qualify it as one of the 100 largest Nasdaq-listed companies, the index is only reranked each December. Stock futures inched mostly lower, following a sharp rally in the previous session, ahead of consumer-sentiment data. Meanwhile, Facebook shares continue to tumble. Chris Dieterich has details on The News Hub. The carnage in Facebook shares has prompted one major question: Is it finally time to buy? Steven Russolillo has the answer on Markets Hub. Photo: Getty. Once-hot social media stocks such as Facebook, Zynga and Groupon have gotten some painful lessons on the effects of supply and demand. Ben Pimentel joins digits to explain how new lows for Facebook and Groupon could may hurt other Web firms contemplating an initial public offering. Photo: Getty Images. Surprise additions do happen—but it is only when a company leaves the index because it falls below listings requirements, seeks bankruptcy protection or is acquired, that unscheduled changes are made. "[December] looks like the most likely time for Facebook to go into the index," a program trader at a large brokerage firm said. Nasdaq's decision to change its index rules was a major factor in Facebook's decision to give its high-profile listing to that exchange rather than the New York Stock Exchange, a person familiar with the matter said at the time. A spokesman for Nasdaq OMX Group Inc., NDAQ -1.22% which operates the Nasdaq Stock Market and the index, declined to comment on index changes. A Facebook spokeswoman also declined to comment on indexing or its impact on the stock. Facebook's History View Interactive Facebook may have to wait even longer to be included in the more-widely followed Standard & Poor's 500-share index. That index provider requires at least six months of seasoning and retains discretion over additions to the index, unlike Nasdaq, which bases changes purely on preset numerical criteria. Google, for example, didn't join the S&P 500 for more than two years after its stock-market listing, despite having a market value that would otherwise have qualified it. "It's not going to be a big deal when Nasdaq adds [Facebook]," said Vijay Singal, a finance professor at Virginia Tech in Blacksburg, Va., who has studied the effects of indexing. "The biggest impact is when S&P 500 adds it ." Inclusion in other indexes hasn't had a lasting impact on Facebook's stock, which has tumbled since its initial public offering. It closed Friday at $19 .05, down 4.1% on the day and nearly half its $38 IPO price—despite being added to broad U.S. stock-market indexes from Russell Investments and MSCI Inc. Investors are focused on slowing revenue growth as well as the company's ability to monetize mobile-phone users. In addition, so-called lockups that prevented some employees and early investors from selling shares have begun to expire, adding to the 421 million already in circulation. Enlarge Image Getty Images Facebook shares were hit this week by the expiration of lockup periods. "There are so many other things going on with Facebook right now," said Amy Lubas, technology strategist at Ned Davis Research Inc. "That is trumping any potential positive index benefits." History suggests that the impact of being added to the S&P 500 is considerably larger, on average, than that for the Nasdaq-100. Companies whose shares were added to the S&P from 2000 to 2010 on average saw a 3.6% increase in the stock price from the announcement of inclusion to the actual addition, according to data compiled by Barclays. The same increase for Nasdaq-100 membership from 2001 to 2012 was about 1.2%. One reason for the gap is that more money is invested across 89 mutual funds and ETFs that directly replicate the S&P 500's moves—$513 billion, according to fund tracker Morningstar Inc. By contrast, the Nasdaq-100 is followed by just $35.5 billion in assets across 11 funds and ETFs, the largest by far of which is the Powershares QQQ Trust QQQ -2.39% ETF, known as "the Qs". For Facebook, the impact of joining any index may be more muted than is typical. In particular, the end of lockups could add two billion shares over the next year will offset some of the index-related buying pressure, said Stuart Thomas, principal at Precidian Investments, which develops ETFs, or funds that can be traded intraday, like a stock. "All the liquidity needed by the indexers will already be there," he said. Additionally, Facebook's poor stock-market performance could lead some funds that follow the index, but don't track it precisely, to purchase less of the stock than they might otherwise have. "The Nasdaq-100 is not a lot of stocks. If Facebook is not up to snuff for some reason, people will know that more easily than they would with a bigger index," said Audrey Costabile, vice president in the applied research group at rival index group MSCI. Facebook's stock has seen brief rises following addition to other indexes, but the gains haven't been sustained. Russell announced on June 11 that Facebook would be added to the Russell 3000 index, and it was added after markets closed on June 22. Facebook enjoyed its best two weeks of price gains during that time, rising 22% to $ 33.05. That period also corresponded to the run-up before analysts published their first research on the stock. But Facebook has yet to return to its June 22 intraday high of $33.45, much less its first-day high of $45.