US East to US Central — the domestic US conversion
One-hour difference. EST is 1 h ahead of CST year-round (and EDT is 1 h ahead of CDT). "10 AM ET / 9 AM CT" is the standard bi-city meeting convention for domestic US multi-office corporations. Domestic banking wire cutoffs, DTCC settlement windows, and NYSE trading hours are all quoted in ET — Chicago-based traders convert reflexively.