What's going on?

On Thursday, US industrial gas company Praxair announced the sale of businesses worth $6 billion to Japan�s Taiyo Nippon Sanso � clearing the way for its multi-billion dollar merger with Germany�s Linde.

What does this mean?

Praxair and Linde are the second and third largest producers of industrial gases (like oxygen tanks in hospitals or helium balloons). Their decision to combine forces at the end of 2016 wasn�t a popular choice with European regulators, who said competition would be too light to give healthy prices to customers.

Praxair hopes that by selling off its European assets, it�ll be allowed to finish the Linde merger and get on with trying to inflate its sales and profits. Taiyo (which, as well as gases, makes Thermos flasks to keep your coffee warm) gets something, too: it�s been trying to become more globally competitive and has set itself a target of getting half its revenues from overseas � so this�ll help.

Why should I care?

For markets: Stocks rose like helium balloons.

Linde�s stock floated up by 2% and Praxair�s by 3% as investors bet that the merger between the companies is now more likely to be approved by regulators. Linde�s also planning to sell parts of its business (worth about $3.5 billion) in order to win approval. Investors will watch closely to see what�s sold � and where � in case it means the company�s planned cost savings (a.k.a. synergies) of $1 billion might be harder to deliver.

The bigger picture: Regulators have chemically castrated M&A in the past.

It took years for US regulators to approve German chemicals conglomerate Bayer�s takeover of Monsanto, an American agricultural chemicals business. They only agreed after Bayer sold parts of its business. Recently, regulators have approved big deals without demanding any concessions (like AT&T buying Time Warner last month) � but first, they need to be convinced that any deal won�t result in unfairly high prices for customers.