[ATTACH] The upper chart shows daily price movements in RAP over...

The upper chart shows daily price movements in RAP over the last 12 months. The lower chart traces movements in the Negative Volume Index (NVI) relative to its 250‑day EMA (red).

The NVI can provide information on the nature of the active market participants. It calculates accumulated price movements only on days when volume is lower than the previous day, and is meant to indicate the involvement of so-called ‘smart money’, usually interpreted as institutional investors.

The NVI commenced a general upward movement in early November (A) that peaked in mid-February (B). The implication is that ‘smart money’ was accumulating during that period. From mid-December to March the NVI was above its 250-day EMA, indicating the expectation of an imminent rise in the share price by those holders.

For those interested in further detail the brief quotes and the links below are informative.

From DayTrading.com
The Negative Volume Index (NVI) trading indicator tracks cumulative changes in volume and is designed to understand when the “smart money” is active.
The central idea is that the “smart money” is most active on days when volume is light and markets are calm. On the other hand, the “not-so-smart money” is most active on days where volume is high and markets are choppier. The general idea is that the “not-so-smart” money tends to be more reactive to market events – especially in an emotional sense – than “smart money”.

From Investopedia
Negative Volume Index trendlines can potentially be the best trendline for following mainstream, smart money movements typically characterized by institutional investors.

From StockCharts
NVI counts price changes when volume decreases and discounts price changes when volume increases. The assumption is that the smart (informed) money is at work when volume decreases and the not-so-smart (uninformed) money is at work when volume increases.
The traditional use of the Negative Volume Index is quite simple. According to Fosback, the odds favor a bull market when NVI is above its 255-day EMA and the odds favor a bear market when NVI is below.