RSI is a front weighted price velocity ratio. The scalpers back off on their asking price until the buyers start biting again. As the supply dwindles, the price of remaining tickets may eventually reach or even exceed their original asking price.
Markets can also drop too far, too fast, and become oversold.
This is akin to an airline overbooking a flight. In such cases the airline often gives up tickets worth more than the value of the oversold tickets. The momentum oscillator is usually characterized by a line on a chart drawn in two dimensions. The vertical axis represents time. Such a momentum oscillator moves very rapidly at market turning points and then tends to slow down as the market continues the directional move.