What Is a Rounding Bottom and Why 8 of Bitcoin's 9 U-Shaped Bases Broke Out

A rounding bottom is a saucer-shaped base where a market drifts lower, flattens out and climbs back to the price it started from, and Bitcoin printed nine of them on Phemex daily bars since December 2023. Eight of the nine cleared the rim within ten sessions, and the ninth never did.

The recount is ours. A fixed rule run over 1,000 Phemex BTCUSDT daily closes, from 20 December 2023 to the Monday 14 September 2026 close of 78,166.4, returns nine non-overlapping episodes and eight completions. The mean ten-session move after the window came to +2.94% and the median to +2.72%. The one failure ran from 14 November to 3 December 2025.

Rounding Bottom at a Glance

What Is a Rounding Bottom?

Sellers run out of conviction and price flattens, then buyers take the other side and the chart traces a saucer. StockCharts ChartSchool is about as close to a neutral authority as this pattern has. It calls the shape a long-term reversal best suited to weekly charts and gives it a second name, the saucer bottom. Confirmation arrives when price breaks above the reaction high that started the decline.

That rim is the whole pattern.

The rounding bottom pattern belongs to the same family as the double top and double bottom patterns, with one difference that decides how you trade it. A double bottom gives you two clean touches and a neckline you can draw with a ruler. A saucer gives you a curve, and where the curve begins is a judgement call you make before the market confirms anything.

How Do You Spot a Rounding Bottom on a Bitcoin Chart?

Three conditions make the shape readable. The decline has to be gradual, the lowest print has to land near the middle of the stretch you are measuring, and the right side has to climb back to roughly where the left side began.

Most traders reach for a smoothing line to see the curve at all. Phemex Academy's guide to trading crypto with the 20 MA shows how a flattening average under price marks the turn into the right half. A rounding bottom breakout still needs the close, though. Until a candle settles above the higher rim, you have a drawing.

The Method Behind the Nine Bitcoin Rounding Bottoms

Definition used: a 20-session window whose lowest close falls in bars 7 to 13, whose first and last closes are within 3% of each other, and whose lowest close is at least 8% below the lower of those two rims. Completion means a daily close above the higher rim inside the next ten sessions. Episodes never overlap, so the scan jumps a full window forward after each hit.

Every one of those numbers is a choice, and the choices move the answer. Widen the window to 30 sessions and the scan returns twelve episodes with ten completions. Tighten the depth test from 8% to 10% and only two survive. Shift the middle-third boundary by one bar and the count stays at nine while the mean ten-session move falls from +2.94% to +2.07%. Shrink the completion test from ten sessions to five and the completions drop from eight to seven.

The bars are Phemex BTCUSDT futures daily candles pulled through the kline endpoint in the Phemex public API docsand cut at the Monday 14 September 2026 close. ChartSchool puts the pattern on weekly charts. This test runs on daily bars, where most crypto traders look, and a weekly series would return a different count from the same rule.

What Happened After Bitcoin's Nine Rounding Bottoms?

Eight of the nine cleared the higher rim inside ten sessions, an 89% hit rate that sounds decisive until you measure the control. Take every trailing 20-session window in the same 1,000 bars and ask the same question. Bitcoin closed above the higher of that window's first and last closes inside ten sessions 594 times out of 971, or 61.2% of the time. The shape beat the field by about 28 points, and it did not invent the move underneath it.

Six of the eight completions cleared the rim on the first session after the window closed. That timing is the tell. A base that breaks out ten sessions later is a different trade from one that breaks the day the shape finishes, and only two of the nine took longer than three sessions.

Why Did the November 2025 Rounding Bottom Fail?

The only failure in the set ran from Friday 14 November to Wednesday 3 December 2025. Bitcoin opened that window at 93,377.2 and bottomed at 84,696.0 on 22 November, 9.30% under the rim. It finished the window at 94,544.6, a textbook saucer by every rule in the test.

Then nothing happened. Ten sessions on, the close stood 3.39% lower, and 94,544.6 held as resistance for the rest of the window. Stretch the completion test to twenty sessions and the episode still fails, which is the cleanest evidence that the curve carries no obligation.

A base that keeps its shape and never breaks out is the argument for picking your risk level in advance. The Phemex guide to stop-loss and take-profit orders in crypto lays out where each order type fires.

What Can a Rounding Bottom Not Tell You?

Nine episodes is a small sample, and the ratio it produces is fragile. One more failure would drop the hit rate from 89% to 80%, and the definition three sections above is the only reason the count is nine at all. Treat the number as a measurement of one rule on one market, never as a property of the pattern.

It also can't tell you how far the move runs. The +2.94% mean covers a spread from -4.12% to +12.61%, and the +2.72% median lands closer to an ordinary Bitcoin fortnight than most chart courses admit. The unconditional ten-session move across the same 1,000 bars averaged +0.89%.

And it can't see the low itself. The deepest point in each window is a close on this test, so the long wick traders remember never enters the arithmetic. Phemex Academy's page on long wick candle reversals covers the shapes a close-only study drops.

Smoothing the curve with the simple moving average on a Bitcoin chart makes it easier to see and adds nothing to the verdict.

What Does Bitcoin's Chart Show Before the 16 September Fed Decision?

The twenty sessions ending Monday 14 September 2026 do not make a rounding bottom. Bitcoin opened that stretch at 78,964.2 on 26 August and closed it at 78,166.4, a gap of 1.01% that passes the rim test comfortably. The window fails on the other two conditions. The lowest close of that stretch came on 10 September at 76,531.2. It is 2.09% under the lower rim and lands in bar 16 of 20, on the right-hand slope where a saucer's low never belongs.

The 50-day average crossed above the 200-day on 8 September and the gap widened to +1.75% by the anchor close. That is a trend reading and not a base.

What to watch: the Federal Reserve announces its rate decision at 18:00 UTC on Wednesday 16 September alongside a fresh set of projections. Saucers form on dull tape, and a policy day with projections attached is the other kind of session.

Bottom Line

Eight completions out of nine reads like an edge until the 61.2% control sits beside it, and what survives the comparison is a smaller claim about a quiet tape. The shape hands you a rim, and a rim is a level you can put an order against. The curve is drawing, and the rim is trading.

Disclaimer: This article is for informational purposes only and is not financial advice. Cryptocurrency trading involves substantial risk. Always do your own research before making investment decisions.