đ€Bubble Carnival or "Baby Bubble"? Indexes & MAG7 Valuation Amid the AI Boom
[Heart]Hello Tigers,
Is the US market curently a Carnival Before the Bubble Bursts or a "Baby Bubble"?[Allin]
On September 25, the three major U.S. stock indices closed lower for the third consecutive day: the $Dow Jones(.DJI)$ fell 0.38%, erasing all gains since the Federal Reserve signaled a "50bp rate cut" on September 18; the $S&P 500(.SPX)$ dropped another 0.5%, with a cumulative 1.8% decline over three days; and the $NASDAQ 100(NDX)$ also fell 0.5%, showing obvious short-term pressure.
Latest Valuation Check-Up: Big-3 Indexes & Mag-7 at a Glance:
Ticker | Latest Price($) | YTD 2025 | TTW P/E | Forward P/E | Average P/E in 10 yrs | Forward P/E VS. Average P/E in 10 yrs |
6656.92 | 12.29% | 29.33 | 25.17 | 19.2 | 31.09% | |
24580.17 | 16.11% | 37.8 | 30.8 | 25.9 | 18.92% | |
46292.78 | 8% | 31.87 | 23.11 | 18.5 | 25% | |
178.43 | 32.32% | 39.39 | 31.46 | 40.95 | -23.17% | |
254.43 | 2.58% | 34.23 | 32.35 | 22.62 | 43.02% | |
509.23 | 20.29% | 32.91 | 32.68 | 28.16 | 16.05% | |
251.66 | 29.47% | 24.85 | 24.21 | 25.24 | -4.08% | |
252.34 | 29.84% | 24.84 | 24.28 | 25.16 | -3.50% | |
220.71 | -0.57% | 32.94 | 25.62 | 70.75 | -63.79% | |
755.4 | 27.91% | 26.97 | 21.43 | 26.14 | -18.02% | |
425.85 | 4.84% | 265.28 | 210.5 | 35.26 | 496.99% |
Read more on >>đ€Market is Expensive? A Glance of MAG 7 âs P/E Ratio in 5 yrs
I. Three Core Triggers for the Three-Day Losing Streak
Powellâs "Bubble Pricking": On September 23, he explicitly stated that "stock market valuations are quite high," which was seen as an oral cooling signal from the Fed. Historical data shows that after a Fed Chair names excessive asset prices, the broader market typically corrects by 5%-7% on average within three months.
"Too Good" Economic Data Turns Negative: The preliminary September Markit Manufacturing PMI hit 54.2 (an 18-month high) and weekly initial jobless claims were below expectations. This pushed the probability of a 25bp rate cut in November down sharply from 74% to 49%, with the "Magnificent Seven" tech stocks falling 1.6% on average.
Trumpâs "Government Shutdown Threat": He called for a federal government shutdown if spending cuts are not approved by October 1. During the 35-day 2018-2019 shutdown, the $S&P 500(.SPX)$ fell 12%, and now sectors like defense and infrastructure are pricing in this political risk early.
II. Valuation Debate: A Repeat of 1929 or a "Baby Bubble"?
Despite short-term corrections, U.S. stocks have still posted solid year-to-date gains:
$S&P 500(.SPX)$ up ~12.29%, $NASDAQ(.IXIC)$ up ~15.92%, and $Dow Jones(.DJI)$ up ~12.58%.
However, views on valuations are sharply divided:
(1) Bears: Warn of a "1929-style Crash"
Mark Spitznagel, founder of black swan fund Universa Investments, warned that the S&P 500 may rise 20% to 8,000 points in the short term but could then plummet 80%. His logic includes: lingering liquidity boosting risk appetite, current "carnival" mirroring pre-1929 crash patterns, and record-high stock allocations by households and institutions.
Short-term liquidity remains abundant: The Fedâs rate cut cycle has not ended, which continues to boost short-term risk appetite. The $S&P 500(.SPX)$ has risen by more than 13% so far this year, and a further 20% increase is "realistically possible";
Historical signals have emerged: Before the 1929 crash, the average annualized return in the 12 months before the bear market started reached 26%, and the index even doubled before peaking. The current market's "doomsday carnival" highly aligns with this characteristic;
Valuations and positions are approaching extreme levels: Long-term low interest rates combined with fiscal bailouts have pushed market valuations to historical highs. The proportion of U.S. household stock allocations has exceeded the peak during the dot-com bubble, and institutional stock exposures have even hit a new high since November 2007.
Metric | Dec 1999 | Sep 2025 | Take-away |
S&P 500 P/E (TTM) | 29.8Ă | 29.3Ă | Slightly lower, still top-5% historic |
Shiller CAPE | 44.2Ă | 37.1Ă | 84% of 1999 level, above 1929 |
Price/Sales | 2.1Ă | 2.9Ă | More expensive than 1999 |
Tech weight in S&P | 29% | 34% | Higher concentration |
Household equity/Fin assets | 22.50% | 20.70% | Knocking on 1999âs door |
New issues + SPACs/Mkt cap | 0.80% | 1.10% | Even more liquidity splash |
(2) Bulls: Itâs a "Baby Bubble"
@Tiger_James Ooi strategist at Tiger Brokers, argues that the $NASDAQ 100(NDX)$ has risen only 120% since the 2023 AI boomâfar less than the 1,073% surge during the 1995-2000 dot-com bubble.
Valuations also support this: the $NASDAQ 100(NDX)$ âs current P/E is 30.7x (vs. its 10-year high of 40x), and the $S&P 500(.SPX)$ âs P/E is still below its 10-year peak.
Data as of September 25th
Data as of September 25th
$Bank of America(BAC)$ âs Michael Hartnett agrees the bubble isnât finished: studying 10 major equity manias since 1900, the average trough-to-peak gain is 244%, implying the Mag-7 still has room to run. Boom phases are narrow and explosiveâtech rallied 61% in six months during 2000 while the rest of the $S&P 500(.SPX)$ fell; todayâs market has yet to reach that âextreme split.â
Hartnett advises hedging with âdistressed valueâ stocks, as prior bursts of mega-cap euphoria ultimately lifted the economy and sparked a catch-up rally in cheaper names.
III. Four Risks of a Bubble Burst (with Probabilities)
Risk Type | Probability | Core Trigger Conditions | Impact on S&P 500 |
|---|---|---|---|
"Rate Hike-induced" Burst | 30% | Core PCE exceeds 3.5% in Q1 2026, forcing the Fed to shift to rate hikes | 35%-50% valuation pullback |
"Earnings Collapse" Burst | 35% | AI capex fails to drive revenue, dragging 2026 earnings growth to 0% (per Barclays: a 20% drop in data center capex could cut earnings by 3-4% and valuations by 10-13%) | 70% of stocks face a "Davis Double Whammy" |
"Liquidity Withdrawal" Burst | 20% | $1.2T in new U.S. Treasuries issued in Q4 2025 + ongoing QT, pushing 10-year Treasury yield above 5% | Triggered stock-bond rebalancing sell-offs |
"Black Swan" Burst | 15% | Escalated Middle East conflicts, cross-strait tensions, etc. | Over 20% flash crash within a week |
IV. Investor Responses: "Three Parachutes"
Institutional-style "Rebalancing": Trim 2% of holdings whenever the portfolio rises 5% to reset to target stock weights.
Option Hedging: Use Sell Put or Buy Put strategies to limit downside risk while holding long positions or call options.
Cross-asset Diversification: Allocate 20% of positions to short-duration high-yield bonds, gold, and undervalued non-U.S. markets (e.g., Japanese stocks, Hong Kong stocks, Latin American markets).
Risk Disclosure: This analysis is based on public market data and historical patterns, and does not constitute investment advice. Investors should make decisions based on their own risk tolerance.
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