Something very odd is going on.

Since the beginning of May, the S&P 500 has risen 314 points - a significant surge.

However, as the chart below shows, more than all of those gains have come when the US equity market is closed.

Yes you are reading that correctly: During the US day session, the S&P has lost 5 points; and during the overnight session (from the cash close to the cash open), the S&P has gained 319 points.

Trade accordingly.