Is the influence of oil prices changes on oil and gas stock prices in Nigeria symmetric or asymmetric?

Overdependence on oil revenue has exposed the economy to shocks from oil price variations. In this paper, we investigated the relationship between oil price on the stock prices of oil and gas firms quoted in the Nigerian Stock Exchange market. In doing so, the ARDL and NARDL approach is applied to estimate quarterly data from 2009q1 to 2016q3. The result from the study showed that negative and positive oil price shocks have a positive long-run influence on stock prices (oil & gas). The evidence further showed that the long-run and short-run impact of an oil price increase on the oil and gas stock price index is similar to that of an oil price decrease. The oil and gas stock price responds positively to oil price shocks in the long run. Therefore, the portfolio managers, potential investors and policymakers in the oil-exporting countries should diversify investments to reduce exposure to risk and uncertainty that may arise to disruptions in the demand and supply for oil and gas or during periods of declining oil prices induced by negative global economic events.