Vulcan Materials’ (VMC) board unanimously rejected a stock-to-stock bid from rival Martin Marietta Materials (MLM) on Thursday, calling the offer “opportunistic,” and encouraged its shareholders to do the same.

The company’s chief executive, Donald James, said the nearly $5 billion offer “does not come close” to appropriately compensating shareholders and is actually disadvantageous to stockholders since it takes advantage of cyclical lows.

Martin Marietta, which proposed on Dec. 12 to buy each Vulcan share for 0.5 Martin Marietta shares, did not immediately respond to FOX Business for a comment. Martin had said earlier this month that the deal offered a “compelling opportunity” for both companies’ shareholders, customers and employees.

However, Goldman Sachs (GS) told the Vulcan board on Dec. 19 that it believed the offer was “inadequate from a financial point of view to such holders.”

“Our Board's position is clear – shareholders should reject Martin Marietta's low-ball and opportunistic exchange offer," James said.

The board concluded after consultation with its independent financial and legal advisors that Vulcan is better positioned to capitalize on an economic recovery than Martin Marietta.

The Birmingham, Al.-based cement and asphalt producer highlighted its stronger presence in the most attractive U.S. markets and more profitable aggregate business, and said it has historically emerged from recessionary periods with significant upside earnings growth.

Vulcan also called the offer illegal, saying Raleigh, N.C.-based Martin Marietta used confidential information from Vulcan to help formulate its offer.

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