When stocks are rallying, levels that had been resistance can convert into support levels. This is bullish for stocks and it may occur with Alphabet Inc. (NASDAQ:GOOGL) and Facebook, Inc. (NASDAQ:FB).

This dynamic happens because of remorseful sellers.

These investors sold their stock at the resistance level, but after it trades at a higher price, they think selling was a mistake. Many decide to buy their shares back.

But they will only do so if they can get them for the same price at which they sold. This way, they can erase their mistake. As a result, they place their buy orders at their sell price.

If there are enough of these buy orders, a level that had been resistance will convert into a support level. If it happens with GOOGL and FB, the stage is set for another move higher.

For GOOGL, the level to watch is $2,390.

The $330 level is important for Facebook.