The long-awaited rally in Activision Blizzard (NASDAQ:ATVI) stock finally has arrived. Activision Blizzard stock plunged in last year’s fourth quarter and spent the first seven-plus months of 2019 trading sideways. Of late, however, ATVI has been on fire.Source: Piotr Swat / Shutterstock.com Indeed, as of Aug. 14, ATVI stock was down 2.8% year-to-date. Since then, its chart shows that Activision Blizzard stock is up 18% year-to-date. The launch of “World of Warcraft Classic” on Aug. 27 appears to have provided a particular boost of late.But the long-term problem for Activision Blizzard that I highlighted back in 2017 still holds. This is not a company that has posted significant earnings growth this decade.InvestorPlace – Stock Market News, Stock Advice & Trading TipsATVI stock has gained nicely, to be sure — and its earnings per share have risen nicely. But that EPS growth has come from three catalysts. First, Activision Blizzard made a huge share repurchase from stakeholder Vivendi (OTCMKTS:VIVHY) at less than $14 per share, a quarter its current price. Second, tax reform increased after-tax income. And, third, the acquisition of King Digital appears to have been a smashing success.The core product portfolio, however, has driven minimal earnings growth for years now. Until and unless that changes, the rally in ATVI stock is going to come to an end. ATVI’s Growth Problem ContinuesBack in 2010, Activision Blizzard posted non-GAAP net income of $991 million. 2019 guidance suggests a much higher figure: $1.4 billion.On its own, that number isn’t all that impressive. It’s a 58% increase total — or about 5.1% annual growth. But consider two other factors. * 7 Momentum Stocks to Buy On the Dip First, Activision Blizzard’s tax rate has come down. The non-GAAP figure was 29% in 2010 and was guided to 20% this year on the second-quarter conference call. That alone created over 12 percentage points of growth. Second, Activision acquired King, whose 2015 net profit was over $600 million. Activision Blizzard’s total growth in nine years is less than that.The two biggest hits in the Activision Blizzard portfolio — “World of Warcraft” and “Call of Duty” — seem to have been relatively stagnant. Elsewhere, performance has been mixed. “Candy Crush” continues to grow, as it and Zynga (NASDAQ:ZNGA) prove there’s more life in social gaming than skeptics believed.But “Overwatch” revenues, according to ATVI’s U.S. Securities and Exchange Commission Form 10-K, declined in both 2017 and 2018. “Diablo” has been solid, but not quite a hit. The same likely is true for “Hearthstone.” “Skylanders” went on hiatus in 2017, despite the fact that Disney (NYSE:DIS) discontinued “Infinity” the year before.Qualitatively, the portfolio seems to have some holes. Even with the launch of Classic, “World of Warcraft” seems long in the tooth. The same is true for “Call of Duty.” Elsewhere, there isn’t anything that really qualifies as a hit. And that seems like a problem given that Activision Blizzard stock now is trading at over 27 times its 2019 EPS guidance. Where’s the Catalyst for Activision Blizzard Stock?If that’s the case, why has ATVI stock rallied? As noted, “World of Warcraft Classic” has posted big numbers, and that appears to have helped lately.But Wall Street also has turned bullish in recent weeks. Activision Blizzard stock has received multiple upgrades this month alone. The “World of Warcraft” re-launch and the new “Overwatch” game for the Nintendo (OTCMKTS:NTDOY) Switch both seem to be helping.The Street sees 2019 adjusted EPS of $2.19 against $2.02 guidance, given Activision Blizzard’s long-running penchant for sandbagging its guidance. 2020 consensus implies 15% growth next year.That said, the rally of late seems to have incorporated that good news. Even backing out net cash, ATVI stock trades at over 21 times forward earnings. The average Street target price is $56.21, less than 1% above Monday’s close of $55.78.And the re-launch of old products might help 2019 and 2020 numbers — but they don’t do much for 2021 and beyond. This still is a company that needs a hit. It hasn’t really had one this entire decade (depending on how an investor feels about “Overwatch”). The company can only go for so long milking existing franchises and cutting costs, as it did with layoffs earlier this year.Esports often is cited as a catalyst, but this is a company with a $42 billion market cap. “Overwatch” franchise fee costs of $50 million don’t necessarily move the needle all that much. Activision Blizzard, and Activision Blizzard stock, need another big-time game. At least at the moment, there doesn’t appear to be one on the horizon. The Case for ATVI StockTo be sure, it’s possible that the existing base is enough, or close. Activision Blizzard can keep repurchasing shares. Esports will help. The re-launches should as well. Investors still look reasonably bullish on video games.But investors at the moment should also heed the lesson of rival Electronic Arts (NASDAQ:EA). EA stock saw a big rally earlier this year when “Apex Legends” opened big. But the initial buzz faded, and so did Electronic Arts stock. It’s down about 7% from those levels in roughly seven months, during which time the broad market has gained and Take-Two Interactive (NASDAQ:TTWO) has bounced some 40%.And it’s worth noting that, backing out its cash, EA stock trades at less than 17 times 2020 consensus EPS, a large discount to ATVI stock. It wouldn’t be stunning to see a similar story play out with Activision Blizzard stock. Fading “World of Warcraft Classic” numbers remove the catalyst from the stock. Forward multiples compress below 20 times. And ATVI heads back below $50. That’s probably not enough for a short case — but it’s certainly enough to be careful after the rally of the past few weeks.As of this writing, Vince Martin has no positions in any securities mentioned. More From InvestorPlace * 2 Toxic Pot Stocks You Should Avoid * 7 Momentum Stocks to Buy On the Dip * 7 Dow Titans Breaking Higher * 5 Growth Stocks to Sell as Rates Move Higher The post Beware the Rally in Activision Blizzard Stock appeared first on InvestorPlace.