What share of MYM's daily trading volume trades after 12:00 PM ET

Methodology

Computed by independently generating and running analysis code against real MYM 1-minute bars from 2026-03-05 to 2026-09-07, 25 separate times in parallel, then taking the answer the largest group of independent attempts agreed on. The exact code is shown below.

bars_et = to_et(bars)
rth = rth_session(bars_et)
rth = rth.copy()
rth['trading_date'] = trading_date(rth)

after_noon = rth.index.time >= pd.Timestamp('12:00').time()

total_vol = rth['volume'].sum()
after_vol = rth.loc[after_noon, 'volume'].sum()

n_days = rth['trading_date'].nunique()

if total_vol > 0 and n_days > 0:
    share = float(after_vol) / float(total_vol)
else:
    share = None

result = {
    'sample_size': int(n_days),
    'share_volume_after_noon_et': share,
    'total_volume': int(total_vol),
    'volume_after_noon': int(after_vol),
}

• Generated and independently re-derived 25 times, then checked for logical consistency, before being shown to you -- the figures above are the answer the largest number of those independent attempts agreed on. Still a generated, one-off calculation, treat it as a rough, one-off analysis rather than a permanent fixture.