Updated from 6:17 a.m. with more on a potential Haversham/BCA Marketplace deal.

LONDON (TheDeal) -- European markets continued their upward march this morning, buoyed by continued European Central Bank bond buying and ahead of the U.S. Federal Reserve's meeting, which starts Tuesday. Germany's DAX index even broke through the 12,000-point barrier for the first time. There is also renewed optimism that China will take new economic stimulus measures to help meet its target of 7% growth.

The FTSE 100 was up 0.47% at 6,772.40. In Paris, the CAC 40 was up 0.63% at 5,042.11. In Frankfurt, the DAX was up 0.87% at 12,006.71. In China, the Shanghai Composite index closed up 2.26% at 3,449.31, while in Hong Kong, the Hang Seng finished the day 0.53% higher at 23,949.65. However, in Tokyo, the Nikkei 225 was just below the flatline, closing down 0.04% at 19,246.06.

In Paris, where the market was otherwise buoyant, cement and building materials group Lafarge (LFRGY) took a tumble after Switzerland's Holcim (HCMLY) announced it was no longer prepared to go ahead with their planned $40 billion merger of equals on the current terms. Lafarge in turn said it was prepared to explore the possibility of revising the parity in line with recent market conditions, but could not accept any other modification of the terms of their existing agreements.

The announcement sent the French group's share down 4.4% to €62.12 a share, but also hit Holcim, which was down 1.46% at Sfr74.30.

A third company to take a beating was Ireland's CRH (CRH). The Dublin-based cement group agreed in February to buy €6.5 billion ($6.85 billion) of assets from Holcim and Lafarge to help them meet regulatory conditions for the merger, but that deal now hangs in the balance too. CRH share tumbled 2.9% to €1,785.

Meanwhile, in London, shares in online kitchen appliance retailer AO World fell 3.5%, to 184.9 pence, on news that non-executive chairman Richard Rose sold a 1.3% stake in the company worth just over £10 million ($14.8 million). The shares had already started slipping after he made the announcement late on Friday and continued their slide this morning. The company staged a strong IPO in 2014, but issued a profit warning last month.

And on London's junior Alternative Investment Market, trading in listed acquisitions vehicle Haversham Holdings was suspended following a report in the Sunday Times newspaper over the weekend that the firm was closing in on a deal to buy BCA Marketplace. BCA, or British Car Auctions, is owned by the U.S. private equity firm Clayton, Dubilier & Rice, which slammed the brakes on a planned IPO of the second-hand car auctioneer last October, citing market volatility at the time.

Haversham issued a statement acknowledging that it was in very advanced discussions that might lead to a reverse takeover of a company, without specifying whether BCA was the target.