Kohl's is getting smoked after missing on earnings across the board

Kohl's shares fell by as much as 6% in pre-market trading after the company reported a drop in net sales for the first time in six quarters.

The department-store chain's results on the most important metrics missed Wall Street's expectations.

Kohl's reported total net sales of $3.97 billion, less than the forecast for $4.13 billion according to Bloomberg.

Sales at established stores fell 3.9%, missing the forecast for a rise by 0.4%. Adjusted earnings per share (EPS) was $0.31, with $0.37 expected.

And just like Gap and Macy's earlier this week, Kohl's earnings show that the industry is still a tough one for retailers.

Convenient online shopping, changing consumer tastes and deep discounts to move excess inventories are all working together to crush retailers.

"First quarter sales were challenging," CEO Kevin Mansell said in the earnings statement.

"Despite the sales environment, we were able to manage our gross margin and inventory levels consistent with our expectations as we took the markdowns necessary to clear excess inventory."

Kohl's shares have fallen 48% over the last year.