LONDON (The Deal) -- European markets opened weaker Monday following further slides in oil prices, with Brent crude down over 0.8% at $40.86 and West Texas Intermediate crude down 1.8% at $38.73. But as the morning developed, markets picked up returning to nearer last week's highs. In part this was said to be due to optimism about potential merger and acquisition moves in the chemicals sector. Bloomberg reported Monsanto (MON) has explored possible deals with German companies BASF (BASFY) and Bayer (BAYRY) .

BASF was up 2.04% at €67.46 while Bayer was up 4.17% at €103.6.

U.K. chemicals producer Synthomer offered further justification for the bounce in the sector when it announced an agreement to buy Hexion of Columbus, Ohio, for $226 million. It said the acquisition of the performance adhesives and coatings maker will grow its presence in the United States and Asia. At the same time, it said it agreed to sell its dispersions business in South Africa to Ferro for £13 million ($18.7 million), citing the unit's declining Ebitda and cash flow. Synthomer was up over 6.8%% at 349.2 pence.

In London, the FTSE 100 was up 0.24% at 6,204.19, while in Paris the CAC 40 was up 0.17% at 4,469.96 and in Frankfurt the DAX was up 1.13% at 10,063.65.

In New York, futures for the S&P 500 rose 0.23%.

In Paris, insurance group AXA dipped sharply at the open but soon recovered, following the announcement that long-serving CEO and Chairman Henri de Castries will step down in September. He will be replaced as CEO by the group's German operations Thomas Buberl, while fellow Frenchman Denis Duverne, deputy chief executive who had been expected to take on both the chairmanship and the chief executive role, will become chairman. By late morning, the share was up about 0.8% at around €21.77.

Some barking was heard at FTSE 250 pet grooming, accessories retailer and veterinary services provider Pets at Home, once owned by Kohlberg, Kravis Roberts & Co. The stock was largely unruffled by the decision of its top dog, CEO Nick Wood, to step down in favor of retail division chief Ian Kellett.

On London's junior Alternative Investment Market, or AIM, electronic invoice processor Tungsten rose over 5.5% to 57.25 pence. Tungsten, which offers an early payment service as a form of alternative finance for businesses waiting for clients to pay their bills, said it had rejected efforts by founder Edmund Truell to get the company to buy minority stakes in his other businesses. Truell was demanding it use the cash raised from the proposed sale of its banking business to finance the scheme. Tungsten said Truell had now resigned from its board.

Japan was closed for a public holiday on Monday, but elsewhere in Asia, the Hang Seng was up 0.06% at 20,684.15 and China's CSI 300, which combines Shanghai and Shenzhen stocks, closed the day up 2.44% at 3,249.44 following the relaxation of certain regulatory restrictions.