Keystone Automotive Industries Inc. said Monday in a regulatory filling that Rockhampton Management UK LLP will vote against the proposed takeover of the company by Chicago-based LKQ Corp. because it undervalues the company.

The deal, which was announced July 17, will pay Keystone shareholders $48 per share, or $811 million, a 10 percent premium on the company’s closing price the day before the deal was announced.

Rockhampton holds about 4 percent of Keystone, which is headquartered in Pomona and makes aftermarket auto parts. Rockhampton has joined other shareholders in their disapproval of the deal which was unanimously approved by Keystone’s board the day the sale was announced.

“I am writing to express my shock and dismay at the entirely inadequate price you and the Keystone Automotive board have unanimously decided to accept,” wrote Saul Rubin, the portfolio manager of Rockhampton, in the letter sent to Keystone at the end of July.

Rubin added that any price below $75 per share is unacceptable in his view.

Shares in Keystone gained 6 cents per share $45.48 in afternoon trading Monday on the Nasdaq.