Maplewood-based 3M Company-which has gone on an acquisition spree over the past few months-seems to have hit a snag in its deal to purchase Cogent, Inc.

3M announced in August its plans to acquire Pasadena, California-based Cogent in a deal valued at $943 million, offering to pay $10.50 per share.

Some Cogent shareholders filed a request to block to proposed sale, but the Delaware Chancery Court denied that request earlier this month.

3M announced Monday that its subsidiary, Ventura Acquisition Corporation, held about 63.1 million Cogent shares-or 71 percent of the company. 3M extended its cash tender offer for Cogent through Tuesday afternoon.

3M said that if, following its extended offer, it owned at least 66.5 million Cogent shares, it would subsequently purchase directly from Cogent however many shares necessary to possess 90 percent of the company's outstanding common stock-completing the acquisition.

If 3M didn't reach that number, however, the company said that it will acquire the remaining shares in “a second-step merger” that will require Cogent shareholder approval.

In either case, 3M said, all remaining shares that it did not acquire would be bought for $10.50 in cash.

On Wednesday, following the close of 3M's extended tender offer, the company said that it now owns about 64.9 million Cogent shares-or 72.1 percent of those outstanding.

3M will therefore need to receive approval at a subsequent Cogent shareholder meeting. 3M said, however, that it has sufficient voting power to approve the merger without needing the votes of other Cogent shareholders.

3M said that it expects the merger to be completed in the fourth quarter.

The company recently announced an investment in Perceptive Pixel, which researches, develops, and produces multi-touch interfaces. The company has also recently completed two acquisitions-Attenti Holdings and Arizant-and announced the acquisition of Alpha Beta Enterprise Company, Ltd.'s tape-related assets.

3M-which provides technologies for the consumer, electronics, health care, industrial, and transportation markets-is among Minnesota's 10-largest public companies based on its 2008 revenue of $25.3 billion. The company reported revenue of $23.1 billion in 2009.