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

Data: ~/data/bars/XAUUSD_mt5_m1.csv, 232,215 minutes from 2026-01-01 18:00 to 2026-08-27 16:59 New York; 170 weekdays. Generated by profile.py on 2026-09-06 06:16 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 = **31.2%** (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, 00:00, 23:00, 00:30 at 8.07, 8.95, 9.18, 10.98 USD vs median bin 12.14 USD → **confirmed**.
- Claim 2, spread, rule as written (17:00–18:00 NY median spread ≥ 2× day median: 1.00×, on 15 days only, because that hour is the broker's break; Asian median spread ≥ 1.5× overlap's: 1.00×) → **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 0.09: 16:59 (0.50). 90th-percentile spread, Asian window 0.11 vs overlap 0.11.

## Movement

Typical whole-day move (root of mean daily realised variance, weekdays): **87.5 USD/oz**; median day 63.3.

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 | 23.77 | 0.0654 | 0.32 | 3.7 | 774.0 |
| 09:30 | 19.7 | 0.0449 | 0.06 | 3.9 | 804.5 |
| 10:30 | 19.17 | 0.0426 | 0.27 | 3.2 | 691.5 |
| 08:30 | 18.32 | 0.0389 | 0.09 | 2.77 | 437.5 |
| 08:00 | 17.39 | 0.035 | 0.24 | 2.54 | 400.0 |
| 11:00 | 16.83 | 0.0328 | 0.1 | 2.94 | 615.0 |

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 | 15.74 | 19.7 | 3.9 |
| 10:00 | 13.95 | 23.77 | 3.7 |
| 10:30 | 12.52 | 19.17 | 3.2 |
| 21:00 | 11.75 | 16.44 | 2.86 |
| 09:00 | 11.67 | 15.62 | 3.02 |
| 11:00 | 11.55 | 16.83 | 2.94 |

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 | 8.07 | 0.0075 | 1.45 | 0.09 | 221.0 |
| 16:30 | 8.94 | 0.0092 | 1.14 | 0.09 | 132.0 |
| 00:00 | 8.95 | 0.0093 | 1.51 | 0.09 | 223.0 |
| 23:00 | 9.18 | 0.0098 | 1.72 | 0.09 | 300.5 |
| 16:00 | 10.3 | 0.0123 | 1.28 | 0.09 | 161.0 |
| 07:00 | 10.3 | 0.0123 | 1.835 | 0.09 | 282.0 |

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 |
|---|---|---|---|---|
| 10:00 | 6.0 | 2.65 | 4.879 | 169 |
| 21:00 | 5.87 | 2.44 | 4.301 | 135 |
| 09:30 | 5.27 | 2.02 | 4.124 | 169 |
| 09:00 | 5.07 | 2.28 | 4.247 | 169 |
| 09:31 | 5.07 | 2.68 | 4.412 | 169 |
| 20:00 | 4.75 | 2.78 | 5.26 | 135 |
| 08:30 | 4.59 | 2.46 | 10.571 | 169 |
| 10:01 | 4.53 | 2.45 | 5.227 | 169 |

## 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 |
|---|---|---|---|
| 10:00 | 0.02 | 0.09 | 3.7 |
| 09:30 | 0.02 | 0.09 | 3.9 |
| 08:30 | 0.03 | 0.09 | 2.77 |
| 09:00 | 0.03 | 0.09 | 3.02 |
| 10:30 | 0.03 | 0.09 | 3.2 |
| 11:00 | 0.03 | 0.09 | 2.94 |

Most expensive:

| New York | spread_over_range | median_spread_usd | median_range_usd |
|---|---|---|---|
| 16:30 | 0.08 | 0.09 | 1.14 |
| 16:00 | 0.07 | 0.09 | 1.28 |
| 19:00 | 0.06 | 0.09 | 1.63 |
| 14:30 | 0.06 | 0.09 | 1.61 |
| 00:00 | 0.06 | 0.09 | 1.51 |
| 00:30 | 0.06 | 0.09 | 1.54 |

## The daily break

Gaps of 30–180 minutes occur 131 times; the bins they end in: 18:00 (119), 19:00 (12). Absolute jump across them: median 3.48 USD, 90th percentile 11.98, max 40.17.

## Day of week

|     |   typical_day_move_usd |   days |   median_spread_usd |
|:----|-----------------------:|-------:|--------------------:|
| Mon |                  91.28 |     34 |                0.09 |
| Tue |                  82.01 |     34 |                0.09 |
| Wed |                  85.48 |     34 |                0.09 |
| Thu |                  96.72 |     35 |                0.09 |
| Fri |                  80.35 |     33 |                0.09 |

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