Stage of supply

Producers

Retailers

Intercept

0.1637712

2649805

P-value

(0.27)

(0.024)

Price t-1

−0.2707294

−0.1750158

P-value

(0.000)

(0.001)

First diff of price

0.1122096

0.107915

P-value

(0.231)

(0.247)

Trend

0.020669

0.0144725

P-value

(0.000)

(0.001)

L

1

1

MacKinnon approximate P-value for Z(t)

0.0046

0.0525