Last 59 trading days. "Overnight" = today's Open vs the PRIOR day's Close
(the same move plotted as the pink dotted line on the chart) — each day's own Open→Close
move is not counted here. Overnight $/% is what you'd have earned holding only from close
to next open; Cum. Index is the running compounded value shown on the chart's pink line.
Date
Prior Close
Overnight $
Overnight %
Cum. Index
Open
High
Low
Close
2026-10-26
$210.33
+1.25
+0.59%
$239.78
$211.58
$225.63
$210.85
$223.35
2026-10-23
$210.10
-0.17
-0.08%
$238.36
$209.93
$215.05
$208.50
$210.33
2026-10-22
$226.59
-9.52
-4.20%
$238.56
$217.07
$217.97
$208.31
$210.10
2026-10-21
$221.06
+4.76
+2.16%
$249.02
$225.82
$228.95
$219.50
$226.59
2026-10-20
$228.05
-4.29
-1.88%
$243.77
$223.76
$227.19
$217.26
$221.06
2026-10-19
$227.80
+8.20
+3.60%
$248.44
$236.00
$236.42
$227.69
$228.05
2026-10-16
$244.79
-6.39
-2.61%
$239.81
$238.40
$239.42
$226.65
$227.80
2026-10-15
$238.01
-9.14
-3.84%
$246.23
$228.87
$245.87
$226.54
$244.79
2026-10-14
$255.39
-7.39
-2.89%
$256.07
$248.00
$250.20
$237.55
$238.01
2026-10-13
$255.24
-9.92
-3.89%
$263.70
$245.32
$260.15
$243.60
$255.39
2026-10-12
$266.28
-5.63
-2.11%
$274.36
$260.65
$263.12
$253.34
$255.24
2026-10-09
$275.29
+4.71
+1.71%
$280.29
$280.00
$281.50
$265.67
$266.28
2026-10-08
$294.37
-7.64
-2.60%
$275.57
$286.73
$286.73
$270.26
$275.29
2026-10-07
$302.56
-11.45
-3.78%
$282.92
$291.11
$300.60
$290.57
$294.37
2026-10-06
$302.90
+4.69
+1.55%
$294.04
$307.59
$308.50
$301.07
$302.56
2026-10-05
$307.49
+0.54
+0.18%
$289.56
$308.03
$311.00
$299.80
$302.90
2026-10-02
$292.34
+14.44
+4.94%
$289.05
$306.77
$318.36
$303.12
$307.49
2026-10-01
$289.66
+4.52
+1.56%
$275.45
$294.18
$297.12
$287.50
$292.34
2026-09-30
$293.67
+0.33
+0.11%
$271.22
$294.00
$295.99
$283.50
$289.66
2026-09-29
$283.33
+7.68
+2.71%
$270.91
$291.00
$301.00
$287.06
$293.67
2026-09-28
$310.32
-4.49
-1.45%
$263.77
$305.83
$307.01
$279.20
$283.33
2026-09-25
$306.34
+12.16
+3.97%
$267.64
$318.50
$325.48
$310.08
$310.32
2026-09-24
$332.56
-13.33
-4.01%
$257.42
$319.23
$326.00
$303.65
$306.34
2026-09-23
$333.20
-1.42
-0.43%
$268.17
$331.78
$336.98
$324.56
$332.56
2026-09-22
$322.90
-3.49
-1.08%
$269.32
$319.41
$334.66
$318.69
$333.20
2026-09-21
$275.61
+18.75
+6.80%
$272.26
$294.36
$324.16
$293.08
$322.90
2026-09-18
$264.90
+4.37
+1.65%
$254.92
$269.27
$275.78
$261.65
$275.61
2026-09-17
$243.98
+18.02
+7.39%
$250.78
$262.00
$267.00
$256.00
$264.90
2026-09-16
$241.83
+5.04
+2.08%
$233.53
$246.87
$252.79
$240.45
$243.98
2026-09-15
$239.01
+2.62
+1.09%
$228.77
$241.62
$253.16
$240.68
$241.83
2026-09-14
$264.79
-22.41
-8.46%
$226.29
$242.38
$249.25
$238.03
$239.01
2026-09-11
$254.18
+3.52
+1.38%
$247.21
$257.70
$267.69
$253.06
$264.79
2026-09-10
$264.23
-11.23
-4.25%
$243.84
$253.00
$257.92
$251.29
$254.18
2026-09-09
$261.53
+0.75
+0.28%
$254.66
$262.27
$274.77
$261.50
$264.23
2026-09-08
$252.09
+9.41
+3.73%
$253.94
$261.50
$267.97
$254.64
$261.53
2026-09-04
$242.59
+6.00
+2.47%
$244.80
$248.59
$255.69
$247.51
$252.09
2026-09-03
$234.86
-3.77
-1.61%
$238.89
$231.09
$244.07
$225.46
$242.59
2026-09-02
$234.82
-1.44
-0.62%
$242.79
$233.38
$236.44
$229.39
$234.86
2026-09-01
$241.91
-7.99
-3.30%
$244.29
$233.92
$235.98
$229.33
$234.82
2026-08-31
$239.05
-0.25
-0.10%
$252.64
$238.81
$243.70
$238.09
$241.91
2026-08-28
$255.21
-4.11
-1.61%
$252.89
$251.10
$251.69
$238.66
$239.05
2026-08-27
$251.06
+4.40
+1.75%
$257.03
$255.46
$267.69
$249.47
$255.21
2026-08-26
$241.56
-1.27
-0.53%
$252.61
$240.29
$252.92
$238.50
$251.06
2026-08-25
$238.78
+6.03
+2.53%
$253.94
$244.81
$247.99
$240.34
$241.56
2026-08-24
$243.32
-6.98
-2.87%
$247.69
$236.34
$240.25
$233.29
$238.78
2026-08-21
$250.72
+2.74
+1.09%
$255.00
$253.46
$255.93
$242.50
$243.32
2026-08-20
$249.34
-2.94
-1.18%
$252.25
$246.40
$251.23
$242.28
$250.72
2026-08-19
$253.32
+3.68
+1.45%
$255.26
$257.00
$267.97
$241.50
$249.34
2026-08-18
$271.43
-14.43
-5.32%
$251.60
$257.00
$258.47
$247.60
$253.32
2026-08-17
$279.44
+5.56
+1.99%
$265.73
$285.00
$287.12
$271.28
$271.43
2026-08-14
$278.65
-0.42
-0.15%
$260.54
$278.23
$281.67
$274.45
$279.44
2026-08-13
$271.87
-4.88
-1.79%
$260.94
$266.99
$290.13
$266.24
$278.65
2026-08-12
$268.93
+11.03
+4.10%
$265.71
$279.96
$280.16
$266.59
$271.87
2026-08-11
$267.85
+5.25
+1.96%
$255.24
$273.10
$273.39
$265.37
$268.93
2026-08-10
$282.57
-1.31
-0.46%
$250.33
$281.26
$282.57
$267.31
$267.85
2026-08-07
$286.68
+12.28
+4.29%
$251.50
$298.96
$299.00
$275.00
$282.57
2026-08-06
$274.58
-7.55
-2.75%
$241.16
$267.03
$295.57
$266.88
$286.68
2026-08-05
$280.56
-6.00
-2.14%
$247.98
$274.56
$281.59
$268.62
$274.58
2026-08-04
$239.06
+14.34
+6.00%
$253.40
$253.40
$283.25
$251.10
$280.56
📈 Overnight % Gain Trend
Cumulative overnight-only return, indexed to 0% on 2026-08-03
(same window as the chart overlay and table above, just plotted as % instead of $).
🗓️ Overnight End-of-Month PnL
One checkpoint per calendar month (value at the last trading day seen that month) from the
same overnight-only cumulative series above. The first and last
month shown may be partial if the data window doesn't start/end on a month boundary.
Month
Start Value
End Value
PnL $
PnL %
2026-08
$239.06
$252.64
+13.58
+5.68%
2026-09
$252.64
$271.22
+18.58
+7.36%
2026-10
$271.22
$239.78
-31.44
-11.59%
📅 Seasonality — Adjusted Close by Year
Each line is one calendar year's adjusted close price (split- and dividend-adjusted, so a stock split does not show as a
crash), or the % change from that year's first trading day in "% from Jan 1" mode, aligned by month/day so the same point in the calendar lines
up across years. Most recent year is drawn thicker. Click a year in the legend to hide/show it.
🌙 Overnight vs. Intraday Return
Overnight (close→next open) Intraday (open→close)
From 2023-09-14 to 2026-10-23 (773 trading days), $1 invested
overnight-only would now be worth $3.10;
$1 invested intraday-only would be worth $1.07.
ARM's historical return has leaned mostly on the overnight session.
This reflects a statistical pattern in past prices, not a trading strategy or investment advice —
it ignores transaction costs and slippage.
🎯 Best Strategy Backtest
See which saved strategy has the best real backtested win-rate on ARM, with buy/sell triggers plotted right on the chart.
Watch an animated paper-trading replay of buying each lower-Bollinger-band touch and selling at the upper band on this stock, with your own capital and look-back, and the profit and loss building up as it plays.