Is there a bubble in the price?
The bubble indicator searches daily prices for the typical pattern of speculative bubbles: a rise that keeps accelerating, overlaid with ever faster oscillations. It shows how many of 26 time windows fit that pattern and when the model expects the bubble to end.
Free during the beta, no ads and no subscription. Once you sign in, this page opens the tool.
How it works
The model is based on Didier Sornette's idea: when many investors imitate each other, a price no longer grows steadily but ever faster toward a critical time (tc). There the bubble ends, often with a crash, sometimes with a calm sideways phase. LPPLS stands for log-periodic power law singularity, the formula for this pattern.
Portfolio Lab fits the formula to 26 time windows reaching back 125 to 750 trading days and checks every fit against filters: exponent, oscillations and critical time must lie within plausible bounds. The confidence is the share of windows that pass all filters. Positive means an accelerating rise, negative an accelerating fall.
Read the result with care: the model also flags bubbles that never burst, and the critical time is very uncertain. A high confidence only means the price pattern fits a bubble over many periods. It is a research tool, not a forecast.
What a result looks like
Sample dataMade-up sample data, no real prices and no recommendation. Calculated with the same methods as the tool itself.
Inputs in this example
Locked: you can't change the inputs in the preview.
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Create accountPrice and LPPLS fit
Computed only with prices up to the cutoff date 30 Jun 2025; in gray, the price afterward.
Logarithmic axis. The fit applies to the window from 3 Jan 2023 (dotted); dashed: tc of the fit shown (30 Jul 2025). Shaded area: 10% to 90% of the qualified tc, dotted their median. m 0.45 · ω 8.9 · B -1.020 · D 0.82 · O 4.8.
After the cutoff date the sample index kept rising until 24 Jul 2025 and then fell by 32% until 23 Dec 2025. This bubble was built in on purpose; in real markets the model also flags bubbles that never burst.
Confidence at earlier cutoff dates
The same calculation with all windows, each using only prices up to that day.
| Valuation date | Positive bubble | Negative bubble |
|---|---|---|
| 28 Jun 2024 | 0% | 0% |
| 31 Dec 2024 | 0% | 0% |
| 31 Mar 2025 | 19% | 0% |
| 30 Jun 2025 | 65% | 0% |
The earlier the cutoff date, the fewer windows fit: the bubble pattern only becomes clear as the bubble matures. The tool shows the history week by week over two years.
Fits per window
Red: filter not met. A window only qualifies if all filters are met.
| Window (days) | tc | m | ω | D | O | Qualified |
|---|---|---|---|---|---|---|
| 125 | 3 Aug 2025 | 0.79 | 9.5 | 0.66 | 2.7 | no |
| 150 | 10 Aug 2025 | 0.74 | 10.2 | 0.64 | 2.9 | no |
| 175 | 8 Aug 2025 | 0.78 | 9.8 | 0.70 | 3.1 | no |
| 200 | 12 Aug 2025 | 0.81 | 10.1 | 0.76 | 3.2 | no |
| 225 | 29 Jul 2025 | 0.74 | 8.9 | 0.74 | 3.5 | no |
| 250 | 20 Jul 2025 | 0.71 | 8.1 | 0.77 | 3.8 | no |
| 275 | 9 Jul 2025 | 0.71 | 7.4 | 0.84 | 4.4 | yes, positive |
| 300 | 18 Jul 2025 | 0.56 | 7.8 | 0.93 | 3.9 | yes, positive |
| 325 | 23 Aug 2025 | 0.31 | 10.0 | 0.88 | 3.6 | no |
| 350 | 19 Aug 2025 | 0.34 | 9.8 | 0.89 | 3.7 | no |
| 375 | 23 Aug 2025 | 0.32 | 10.0 | 0.86 | 3.8 | no |
| 400 | 20 Aug 2025 | 0.35 | 9.8 | 0.96 | 3.9 | yes, positive |
| 425 | 21 Aug 2025 | 0.37 | 9.9 | 1.09 | 3.9 | yes, positive |
| 450 | 14 Aug 2025 | 0.37 | 9.4 | 1.02 | 4.0 | yes, positive |
| 475 | 28 Jul 2025 | 0.38 | 8.6 | 0.91 | 4.4 | yes, positive |
| 500 | 27 Jul 2025 | 0.38 | 8.6 | 0.90 | 4.4 | yes, positive |
| 525 | 3 Aug 2025 | 0.38 | 8.9 | 0.90 | 4.4 | yes, positive |
| 550 | 5 Aug 2025 | 0.38 | 9.0 | 0.89 | 4.5 | yes, positive |
| 575 | 4 Aug 2025 | 0.40 | 9.0 | 0.86 | 4.6 | yes, positive |
| 600 | 1 Aug 2025 | 0.43 | 9.0 | 0.83 | 4.7 | yes, positive |
| 625 | 1 Aug 2025 | 0.44 | 8.9 | 0.82 | 4.8 | yes, positive |
| 650 | 30 Jul 2025 | 0.45 | 8.9 | 0.82 | 4.8 | yes, positive |
| 675 | 23 Jul 2025 | 0.49 | 8.6 | 0.82 | 5.1 | yes, positive |
| 700 | 14 Jul 2025 | 0.54 | 8.2 | 0.83 | 5.5 | yes, positive |
| 725 | 26 Jun 2025 | 0.62 | 7.6 | 0.88 | 6.8 | yes, positive |
| 750 | 28 Jun 2025 | 0.62 | 7.6 | 0.87 | 8.0 | yes, positive |
Filters: tc close to the cutoff date, exponent m, log frequency ω, damping D and number of oscillations O.
Assumptions: Prices are made up: a random walk, from 03/2023 a bubble built in with the LPPLS formula ending on 25 Jul 2025, then a crash. Computed with the tool's windows and filters, without prices after the cutoff date.
Frequently asked questions
What is a speculative bubble?
A rise that detaches from fundamentals such as earnings or interest rates and feeds mainly on the expectation of further price gains. Well-known examples are tech stocks around 2000 and Japanese stocks in the late 1980s.
What does the confidence mean?
The share of the 26 time windows whose LPPLS fit passes all filters. 50% means the bubble pattern fits in 13 of 26 windows. Even 10 to 20% stands out, because the page takes the best result across the whole search space for each window.
What is the critical time tc?
The point in time the formula runs toward and at which the bubble ends. The page shows the median of the qualified windows with a range. It is a model value and very uncertain, not a date for a crash.
Which markets does this work for?
Any market with long daily price histories: major stock indexes, bond ETFs, commodities and crypto, plus any ticker of your own. With a cutoff date in the past you can check what the model would have flagged before well-known peaks.
Learn more in the knowledge base
- MethodologyBubble indicator (LPPLS): methodology
- ArticleSpeculative bubbles: what they are and how the LPPLS model detects them
- ArticleShiller P/E (CAPE): how expensive is the stock market?
- ArticleThe efficient market hypothesis: why it is so hard to beat the market
- ArticleHistorical stress testing: how to apply past crises to your portfolio today
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