# Results: gold by the half hour, New York clock

Data: ~/data/bars/XAUUSD_m1.csv, 133,896 minutes from 2026-01-01 18:00 to 2026-06-17 04:59 New York; 119 weekdays. Generated by profile.py on 2026-09-06 06:35 UTC. Definitions in README.md.

## Verdicts

- Claim 1, overlap (08:00–12:00 NY carries > 33% of daily variance and the busiest half hour): share = **31.9%** (pro rata would be 16.7%), busiest half hour = **10:00** → **partly**.
- Claim 1, Asian quiet (four quietest bins in 19:00–03:00 NY all below the day's median bin): quietest four = 23:30, 23:00, 00:00, 22:30 at 8.24, 9.54, 9.71, 12.27 USD vs median bin 13.62 USD → **confirmed**.
- Claim 2, spread, rule as written (17:00–18:00 NY median spread ≥ 2× day median: nan×, on 0 days only, because that hour is the broker's break; Asian median spread ≥ 1.5× overlap's: 1.07×) → **refuted**.
- Claim 2, measured at the edges of the break instead (added after seeing that the 17:00 hour is the break): minutes in 16:45–16:59 and 18:00–18:14 whose median spread is ≥ 2× the day's median of 0.70: 16:59 (1.83), 18:00 (1.45). 90th-percentile spread, Asian window 0.99 vs overlap 0.99.

## Movement

Typical whole-day move (root of mean daily realised variance, weekdays): **90.2 USD/oz**; median day 61.6.

Busiest half hours (typical move = root mean realised variance in the bin, USD/oz):

| New York | typical_move_usd | variance_share | largest_day_share | median_range_usd | median_ticks_per_min |
|---|---|---|---|---|---|
| 10:00 | 27.98 | 0.0748 | 0.38 | 4.13 | 545.0 |
| 09:30 | 22.36 | 0.0478 | 0.07 | 4.47 | 584.0 |
| 10:30 | 21.79 | 0.0454 | 0.35 | 3.55 | 484.0 |
| 20:00 | 19.55 | 0.0365 | 0.16 | 2.99 | 278.0 |
| 11:00 | 19.32 | 0.0357 | 0.13 | 3.29 | 447.0 |
| 21:00 | 18.88 | 0.0341 | 0.23 | 3.08 | 307.0 |

The same ranking on the median day instead of the mean (root of the median daily variance in the bin), which one wild day cannot move:

| New York | median_day_move_usd | typical_move_usd | median_range_usd |
|---|---|---|---|
| 09:30 | 17.2 | 22.36 | 4.47 |
| 10:00 | 15.54 | 27.98 | 4.13 |
| 10:30 | 14.09 | 21.79 | 3.55 |
| 11:00 | 12.52 | 19.32 | 3.29 |
| 09:00 | 12.25 | 17.28 | 3.25 |
| 21:00 | 12.07 | 18.88 | 3.08 |

Quietest half hours (bins present on more than half the days):

| New York | typical_move_usd | variance_share | median_range_usd | median_spread_usd | median_ticks_per_min |
|---|---|---|---|---|---|
| 23:30 | 8.24 | 0.0065 | 1.539 | 0.727 | 141.0 |
| 23:00 | 9.54 | 0.0087 | 1.82 | 0.727 | 191.0 |
| 00:00 | 9.71 | 0.009 | 1.615 | 0.71 | 142.0 |
| 05:30 | 10.55 | 0.0106 | 1.915 | 0.63 | 186.0 |
| 16:30 | 10.58 | 0.0107 | 1.35 | 0.72 | 103.0 |
| 05:00 | 11.26 | 0.0121 | 1.96 | 0.62 | 194.5 |

Minutes with the largest median 1-minute range (the shape inside the half hours; minutes.csv has all 1,440):

| minute NY | median range | median abs move | RMS move | days |
|---|---|---|---|---|
| 21:00 | 6.35 | 2.52 | 4.59 | 75 |
| 10:00 | 6.12 | 2.49 | 4.678 | 93 |
| 09:30 | 5.887 | 2.03 | 4.908 | 97 |
| 09:31 | 5.793 | 3.05 | 5.102 | 97 |
| 08:30 | 5.713 | 3.147 | 8.918 | 97 |
| 20:00 | 5.71 | 2.93 | 6.287 | 76 |
| 09:32 | 5.22 | 2.39 | 5.136 | 97 |
| 09:45 | 5.19 | 2.57 | 4.542 | 97 |

## Cost against movement

Cheapest half hours to trade (median spread as a multiple of the median 1-minute range):

| New York | spread_over_range | median_spread_usd | median_range_usd |
|---|---|---|---|
| 09:30 | 0.16 | 0.71 | 4.47 |
| 10:00 | 0.17 | 0.687 | 4.13 |
| 10:30 | 0.19 | 0.67 | 3.55 |
| 09:00 | 0.21 | 0.67 | 3.25 |
| 11:00 | 0.21 | 0.68 | 3.29 |
| 08:30 | 0.22 | 0.67 | 3.03 |

Most expensive:

| New York | spread_over_range | median_spread_usd | median_range_usd |
|---|---|---|---|
| 16:30 | 0.53 | 0.72 | 1.35 |
| 23:30 | 0.47 | 0.727 | 1.539 |
| 16:00 | 0.46 | 0.67 | 1.45 |
| 00:00 | 0.44 | 0.71 | 1.615 |
| 19:00 | 0.41 | 0.827 | 2.0 |
| 00:30 | 0.41 | 0.71 | 1.735 |

## The daily break

Gaps of 30–180 minutes occur 103 times; the bins they end in: 18:00 (67), 07:00 (5), 00:00 (4). Absolute jump across them: median 5.86 USD, 90th percentile 19.11, max 83.21.

## Day of week

|     |   typical_day_move_usd |   days |   median_spread_usd |
|:----|-----------------------:|-------:|--------------------:|
| Mon |                  96.92 |     24 |                0.69 |
| Tue |                  83.83 |     24 |                0.71 |
| Wed |                  84.7  |     24 |                0.69 |
| Thu |                 102.42 |     24 |                0.71 |
| Fri |                  80.52 |     23 |                0.7  |

Full table: bins.csv (48 rows). Not advice; one broker, one instrument, eight months.