根据一位华尔街顶尖策略师的计算，截至上周五，美国股市总市值已飙升至国内生产总值（GDP）的363%，这一惊人比例远远超过了互联网泡沫时期的历史记录212%。若你认为这种情形不可持续，这无疑是一记警钟。但摩根资产管理（JP Morgan Asset Management）首席全球策略师戴维·凯利指出，这轮牛市确实堪称史诗级，“尽管偶有中断，但其脉络可一路追溯至20世纪80年代。”
美股市场的上涨势头似乎势不可挡，主要受到人工智能热潮、少数超高市值科技股以及高企的市盈率所驱动。这波行情已引发激烈争论：投资者是否正处于又一个历史性泡沫的边缘？
标普500指数的持续攀升已将股价推至历史高位。据《财富》杂志肖恩·塔利近期报道，该指数在8月创下6,501点的收盘纪录，使其追踪市盈率（按实际通用会计准则盈利计算，而非华尔街预测数据）达到30倍。塔利指出，如此高的市盈率在美股市场极其罕见，仅在1999年至2002年的科技热潮以及近期几次收益骤降的危机期间短暂出现过。作为对比，到2022年，投资者每投资100美元可获得5美元收益；如今仅能获得3美元。令人惊讶的是，收益本身几乎未能跑赢通胀，这意味着股价暴涨几乎完全来自市盈率的飙升，而非企业利润增长。
凯利在周一的一份题为《喧嚣牛市的基础》（Checking the Foundations of a Roaring Bull Market）的分析报告中给出了自己的计算结果。在这轮长达数十年的史诗级牛市开启之前，即1955年第三季度至1985年第三季度期间，美国股市总价值平均占GDP的72%。凯利写道，此后发生的一切令人瞩目，“市场涨幅主要并非来自经济增长，而是源于利润的GDP占比提升以及更高的市盈率倍数。”他补充道，支撑这轮喧嚣牛市的“基础”正变得“日益高耸”，而且可能难以持续。
凯利的观点与多位评论员关于自20世纪80年代罗纳德·里根时代以来美国经济“金融化”的警告不谋而合。《金融时报》专栏作家拉娜·福鲁哈尔（时任《时代》杂志记者）曾就此主题著有《大掠夺》（Makers and Takers）一书，书中剖析了当时普遍存在的金融表现已与基本面脱节的证据。亚当·麦凯根据迈克尔·刘易斯非小说类经典作品改编的电影《大空头》（The Big Short）就是一个关键例证。而早在20世纪80年代，奥利弗·斯通的经典电影《华尔街》（Wall Street）就曾生动地捕捉这些动态，片中那句经典台词令人记忆犹新：“贪婪是好事。”
AI炒作：泡沫还是突破？
当前的估值狂潮在很大程度上聚焦于人工智能和科技领域。近期发布的GPT-5虽被誉为一场潜在革命，但未能达到最狂热的预期，这加剧了科技板块的紧张情绪，并导致标普500指数市值在夏季蒸发约1万亿美元。长期批评AI的加里·马库斯指出，行业内生成式AI项目的失败率高达95%，且市场心理与过去的狂热期如出一辙——即“聪明人因为窥见一点点真相就过度兴奋”，从而脱离现实。阿波罗全球管理公司（Apollo Global Management）首席经济学家托斯滕·斯洛克等人认为，当前标普500上领跑的股票，尤其是AI驱动的巨头，相对于其基本面而言估值过高，高估程度比20世纪90年代互联网泡沫时期领跑的公司更为严重。
数据中心投资大幅飙升，其对2025年初GDP增长的贡献度，竟能与消费者总支出相匹敌，这引发担忧：企业是否过度押注于一个可能无法带来短期利润的趋势？AI独角兽公司的估值已膨胀至2.7万亿美元，但全行业范围内的营收和利润有限，这让人们担忧繁荣能否持续。
美联储（Federal Reserve）主席杰罗姆·鲍威尔近期对记者表示，美联储观察到与AI基础设施（以数据中心形式）建设相关的"异常庞大的经济活动量"。当然，市盈率倍数最高的依然是科技板块，特别是那些驱动高度集中的标普500指数的AI股票，例如全球估值最高的公司英伟达（Nvidia）。
疲弱的经济基础
令人担忧的是，这些历史新高诞生的大背景，却是经济增长乏力和劳动力市场出现困境的迹象。7月份就业报告显示新增就业岗位仅7.3万个，而过去三个月的净新增就业岗位仅10.6万个——远低于去年的增速。2025年上半年GDP年化增长率仅为1.75%，较2024年末大幅下降，也远低于抑制不断膨胀的联邦债务所需的水平。如此疲软的增长进一步削弱了当前股票估值的合理性，因为当前的估值几乎完全由市盈率上升驱动，而非企业业绩改善。
对于普通投资者而言，这意味着一个代价高昂的隐患：股价高企是因为他们将企业盈利哄抬到了只有在互联网泡沫或疫情上涨最疯狂的行情里才出现过的水平。随着牛市持续攀升至远高于实体经济增速的高度，经验丰富的策略师建议投资者为市场动荡做好准备，方法是实现投资组合多元化，将投资范围拓展至美国大型公司以外的领域，增加对国际股票、核心固定收益资产和另类资产的投资。
凯利对未来走势持乐观态度，他认为这轮牛市持续的时间已远超任何人的预期，因此当前预测未来非常困难，但他同时认为采取多元化投资策略是明智之举。尽管如此，数据确实引人注目。他发现，从1955年第三季度到1985年第三季度，标普500指数（包括股息）平均年化总回报率为8.8%。“而在之后的40年里，其年化回报率达到了惊人的11.6%。”
《财富》杂志使用生成式AI辅助完成本文的初稿。编辑在发表前已核实信息的准确性。（*）
译者：刘进龙
审校：汪皓
根据一位华尔街顶尖策略师的计算，截至上周五，美国股市总市值已飙升至国内生产总值（GDP）的363%，这一惊人比例远远超过了互联网泡沫时期的历史记录212%。若你认为这种情形不可持续，这无疑是一记警钟。但摩根资产管理（JP Morgan Asset Management）首席全球策略师戴维·凯利指出，这轮牛市确实堪称史诗级，“尽管偶有中断，但其脉络可一路追溯至20世纪80年代。”
美股市场的上涨势头似乎势不可挡，主要受到人工智能热潮、少数超高市值科技股以及高企的市盈率所驱动。这波行情已引发激烈争论：投资者是否正处于又一个历史性泡沫的边缘？
标普500指数的持续攀升已将股价推至历史高位。据《财富》杂志肖恩·塔利近期报道，该指数在8月创下6,501点的收盘纪录，使其追踪市盈率（按实际通用会计准则盈利计算，而非华尔街预测数据）达到30倍。塔利指出，如此高的市盈率在美股市场极其罕见，仅在1999年至2002年的科技热潮以及近期几次收益骤降的危机期间短暂出现过。作为对比，到2022年，投资者每投资100美元可获得5美元收益；如今仅能获得3美元。令人惊讶的是，收益本身几乎未能跑赢通胀，这意味着股价暴涨几乎完全来自市盈率的飙升，而非企业利润增长。
凯利在周一的一份题为《喧嚣牛市的基础》（Checking the Foundations of a Roaring Bull Market）的分析报告中给出了自己的计算结果。在这轮长达数十年的史诗级牛市开启之前，即1955年第三季度至1985年第三季度期间，美国股市总价值平均占GDP的72%。凯利写道，此后发生的一切令人瞩目，“市场涨幅主要并非来自经济增长，而是源于利润的GDP占比提升以及更高的市盈率倍数。”他补充道，支撑这轮喧嚣牛市的“基础”正变得“日益高耸”，而且可能难以持续。
凯利的观点与多位评论员关于自20世纪80年代罗纳德·里根时代以来美国经济“金融化”的警告不谋而合。《金融时报》专栏作家拉娜·福鲁哈尔（时任《时代》杂志记者）曾就此主题著有《大掠夺》（Makers and Takers）一书，书中剖析了当时普遍存在的金融表现已与基本面脱节的证据。亚当·麦凯根据迈克尔·刘易斯非小说类经典作品改编的电影《大空头》（The Big Short）就是一个关键例证。而早在20世纪80年代，奥利弗·斯通的经典电影《华尔街》（Wall Street）就曾生动地捕捉这些动态，片中那句经典台词令人记忆犹新：“贪婪是好事。”
AI炒作：泡沫还是突破？
当前的估值狂潮在很大程度上聚焦于人工智能和科技领域。近期发布的GPT-5虽被誉为一场潜在革命，但未能达到最狂热的预期，这加剧了科技板块的紧张情绪，并导致标普500指数市值在夏季蒸发约1万亿美元。长期批评AI的加里·马库斯指出，行业内生成式AI项目的失败率高达95%，且市场心理与过去的狂热期如出一辙——即“聪明人因为窥见一点点真相就过度兴奋”，从而脱离现实。阿波罗全球管理公司（Apollo Global Management）首席经济学家托斯滕·斯洛克等人认为，当前标普500上领跑的股票，尤其是AI驱动的巨头，相对于其基本面而言估值过高，高估程度比20世纪90年代互联网泡沫时期领跑的公司更为严重。
数据中心投资大幅飙升，其对2025年初GDP增长的贡献度，竟能与消费者总支出相匹敌，这引发担忧：企业是否过度押注于一个可能无法带来短期利润的趋势？AI独角兽公司的估值已膨胀至2.7万亿美元，但全行业范围内的营收和利润有限，这让人们担忧繁荣能否持续。
美联储（Federal Reserve）主席杰罗姆·鲍威尔近期对记者表示，美联储观察到与AI基础设施（以数据中心形式）建设相关的"异常庞大的经济活动量"。当然，市盈率倍数最高的依然是科技板块，特别是那些驱动高度集中的标普500指数的AI股票，例如全球估值最高的公司英伟达（Nvidia）。
疲弱的经济基础
令人担忧的是，这些历史新高诞生的大背景，却是经济增长乏力和劳动力市场出现困境的迹象。7月份就业报告显示新增就业岗位仅7.3万个，而过去三个月的净新增就业岗位仅10.6万个——远低于去年的增速。2025年上半年GDP年化增长率仅为1.75%，较2024年末大幅下降，也远低于抑制不断膨胀的联邦债务所需的水平。如此疲软的增长进一步削弱了当前股票估值的合理性，因为当前的估值几乎完全由市盈率上升驱动，而非企业业绩改善。
对于普通投资者而言，这意味着一个代价高昂的隐患：股价高企是因为他们将企业盈利哄抬到了只有在互联网泡沫或疫情上涨最疯狂的行情里才出现过的水平。随着牛市持续攀升至远高于实体经济增速的高度，经验丰富的策略师建议投资者为市场动荡做好准备，方法是实现投资组合多元化，将投资范围拓展至美国大型公司以外的领域，增加对国际股票、核心固定收益资产和另类资产的投资。
凯利对未来走势持乐观态度，他认为这轮牛市持续的时间已远超任何人的预期，因此当前预测未来非常困难，但他同时认为采取多元化投资策略是明智之举。尽管如此，数据确实引人注目。他发现，从1955年第三季度到1985年第三季度，标普500指数（包括股息）平均年化总回报率为8.8%。“而在之后的40年里，其年化回报率达到了惊人的11.6%。”
《财富》杂志使用生成式AI辅助完成本文的初稿。编辑在发表前已核实信息的准确性。（*）
译者：刘进龙
审校：汪皓
A leading Wall Street strategist is doing some calculations about the total value of U.S. stocks rocketing to a staggering 363% of GDP as of last Friday, blowing past the infamous 212% mark reached during the dotcom bubble. It’s a warning if you think it’s unsustainable, but David Kelly, chief global strategist for JP Morgan Asset Management, notes that the bull market is truly epic, “stretching, with some interruptions, all the way back to the 1980s.”
The market’s seemingly unstoppable rise—driven largely by feverish enthusiasm for artificial intelligence, a few mega-cap tech stocks, and lofty price-to-earnings (P/E) multiples—has set off a heated debate about whether investors are now perched on the edge of another historic bubble.
The S&P 500’s relentless march has led to some of the most expensive stock prices on record. As recently as August, Fortune‘s Shawn Tully reported, the index reached a record close at 6,501, sending its trailing P/E ratio (using actual GAAP earnings, not wall-street projections) to 30x. Tully noted that this territory has been seen only during rare moments in market history, including the tech frenzy from 1999 to 2002, and briefly in recent crises when earnings collapsed. For context, investors were getting $5 of earnings for every $100 invested as recently as 2022; today, they’re getting just $3. What’s striking is that earnings themselves have barely kept up with inflation, meaning that the epic climb in stock prices has come almost entirely from surging multiples, rather than corporate profit growth.
Kelly offered his own calculation in a Monday analyst note, “Checking the Foundations of a Roaring Bull Market.” Until the start of this epic, multi-decade rally, the value of all U.S. equities had averaged 72% of GDP between the third quarter of 1955 and the third quarter of 1985. What has transpired since has been remarkable, Kelly writes, and “the biggest part of market gains have not come from economic growth but rather from a rising profit share of GDP and higher P/E multiples.” Kelly adds that the “scaffolding supporting this roaring bull market” is “increasingly lofty”—and possibly unsustainable.
Kelly’s thesis fits with warnings from several commentators about a “financialization” of the U.S. economy since the age of Ronald Reagan in the 1980s. Financial Times columnist Rana Foroohar, then of Time, wrote a book on the subject called “Makers and Takers,” and touched on the evidence everywhere in the zeitgeist that financial performance had become detached from fundamentals. “The Big Short,” Adam McKay’s adaptation of the Michael Lewis non-fiction classic, was a key piece of evidence. These dynamics were memorably captured on cinema during the actual 1980s, in Oliver Stone’s classic “Wall Street,” which included the memorable line: “Greed is Good.”
AI hype: bubble or breakthrough?
Much of this valuation mania is focused on AI and tech. The recent launch of GPT-5, greeted as a potential revolution, failed to live up to the wildest expectations, fueling tech-sector jitters and a $1 trillion sell-off in the S&P 500 during the summer. Veteran AI critic Gary Marcus points to the dismal 95% failure rate of generative AI projects in industry and a market psychology reminiscent of previous manias—where “smart people get overexcited about a kernel of truth” and disconnect from reality. Apollo Global Management’s chief economist Torsten Slok and others have argued that today’s S&P 500 leaders, especially AI-driven giants, are even more overvalued relative to their fundamentals than their 1990s dotcom counterparts.
Data center investments have soared—so much so that their contribution to GDP growth in early 2025 has matched that of all consumer spending, raising concerns that companies are overcommitting to a trend that may not deliver near-term profits. AI unicorn valuations have ballooned to $2.7 trillion, but with limited industrywide revenue and profits, raising worries about whether the boom is sustainable.
Federal Reserve chair Jerome Powell recently told reporters that the central bank was seeing “unusually large amounts of economic activity” related to the buildout of AI infrastructure in the form of data centers. Of course, the multiples are most outsized in the tech sector, specifically the AI stocks driving the heavily concentrated S&P 500, such as the world’s most valuable company, Nvidia.
Weakening economic foundations
Worryingly, these record highs are being notched against a backdrop of tepid economic growth and signs of labor market trouble. July’s jobs report showed just 73,000 new hires, while the past three months saw only 106,000 net new jobs—a fraction of last year’s pace. GDP growth is languishing at an annualized rate of 1.75% for the first half of 2025, down sharply from late 2024 and well below the levels needed to tame the swelling federal debt. Such sluggish growth further undermines the case for current equity valuations, which have been driven almost exclusively by rising multiples, not improved corporate performance.
For ordinary investors, this means a very costly catch: stock prices are high because they’ve bid up the same dollar of corporate profit to levels seen only in the wildest days of the dotcom or pandemic run-ups. As the bull market floats higher and higher above underlying economic growth, seasoned strategists recommend preparing portfolios for turbulence by diversifying beyond U.S. mega-caps, increasing exposure to international stocks, core fixed income, and alternatives.
Kelly is sanguine about what may happen, reasoning that the bull market has run longer than anyone could ever expect, so prognosticating is difficult at this point, while advising diversification as a sound strategy. Still, the data is remarkable. Between 3Q55 and 3Q85, he finds, the S&P500 provided an 8.8% total return each year, on average, including dividends. “In the 40 years since, it has returned an astounding 11.6% per year.”
For this story, Fortune used generative AI to help with an initial draft. An editor verified the accuracy of the information before publishing.