The daily S&P 500 (SPX) chart courtesy of Trading View updates the action.

The SPX is close to a Fibonacci .382 retracement of the 02/19/25 to 03/13/25 decline. This level was illustrated in the 03/15/25 blog “U.S. Stocks Could Rally into 03/19/25”.
The potential resistance level is near the SPX 200 – day Simple Moving Average (SMA). This is perhaps the most widely watched indicator and sometimes it can be a self-fulfilling prophecy. Frequently, when the SPX breaks decisively below the 200 – day SMA, stock fund managers sell as the SPX rises back up to the line.
Assuming the SPX has not made a rally peak today – 03/19/25, the SPX could make an important top at the dual resistance zone on 03/20/25.