The boss of Europe's biggest manufacturing company has told Sky News that he is "confident and optimistic" that Britain will "find its way" through the turbulence of Brexit.
He was the first business leader to meet Theresa May since the triggering of Article 50 - a German industrialist debating the fall-out of Brexit.
But few would question Siemens' importance to the British economy.
The company has had a presence in Britain for 167 years, and employs 15,000 people here.
It recently invested more than £300m into a renewable energy project in Hull, and Kaeser told me he still sees the UK as one of the "two most powerful economic environments in Europe", along with Germany.
He foresees, he said, "big opportunities in the UK".
Siemens backed the Remain campaign before the referendum, but Mr Kaeser said he had little desire to dwell on the past. Instead, he said he wanted to deal, as well as he could, with the challenges thrown up by Brexit.
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So what did he talk about with Mrs May?
"There was no specific area," said Mr Kaeser. "We talked about economic conditions, about skills and renewable energy.
"We wanted to understand the policy about renewables going forward.
"As a great employer, one of things we prize is political consistency and clear policy."
I understand he found consensus on issues such as skills training and education in the energy sector.
But Brexit remains a more contentious topic.
On that subject, he says Mrs May was "a good listener".
Mr Kaeser had plenty to say.
When analysing the state of the UK economy, he draws a significant difference between Siemens goods that are both made and sold in Britain, and those that are made for the export market.
He is bullish about the former, telling me: "There is no reason not to invest tomorrow, if there is a demand and a commitment from the customer.
"I am willing - and the company is willing to invest - further. There are more opportunities than risks for us."
But he seems much less certain when we talk about products made to be sold around the world.
He talks about the need for "ecosystem of engineering and manufacturing", which will depend upon new relationships between the UK and the continent.
We talk about the prospect of tariffs being imposed on sales between the UK and mainland Europe, be he seems sanguine.
"Tariffs would mean prices going up, and customers don't want higher prices. And remember that customers are also voters."
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But what of the rest of the future trading structure?
"If you look at the letter from the Prime Minister, it is the explicit will of her and the Government to have free trade, close relationships and co-operation.
"But it would be fair to assume it cannot be as good as it would have been in a world where you give and take.
"If you look at Europe, Germany is the powerhouse of manufacturing and the UK is the powerhouse of financial services - the two together would be the perfect match.
"But now we do need to find a way for Europe - geographic, if not political, Europe - to be competitive with China and the United States."
It is that battle with the global superpowers that concerns Kaeser.
"I'm a father with two daughters and I don't want them to feel that they have to go and work in China when they are older," he said.
But it's not his main concern.
When I ask what would be the single most important element he would like to see included in the UK's agreement with Europe, he ponders and then replies, emphatically, that it is free movement of labour.
The most important and also, perhaps, the most controversial.