In the age of Trump, America’s biggest foreign creditors are suddenly having second thoughts about financing the US government.

In Japan, the largest holder of Treasuries, investors culled their stakes in December by the most in almost four years, the ministry of finance’s most recent figures show. What’s striking is the selling has persisted at a time when going abroad has rarely been so attractive. And it’s not just the Japanese. Across the world, foreigners are pulling back from US debt like never before.

From Tokyo to Beijing and London, the consensus is clear: few overseas investors want to step into the $13.9 trillion US Treasury market right now. Whether it’s the prospect of bigger deficits and more inflation under President Donald Trump or higher interest rates from the Federal Reserve, the world’s safest debt market seems less of a sure thing.

Foreigners still hold $5.94 trillion, or roughly 43% of the US government debt market (down from 56% in 2008.) A significant drawdown can harm major holders such as Japan and China as much as it does the US. And, of course, homegrown demand has of late been able to absorb the pickup in overseas selling. Since reaching 2.64% in mid-December, yields on benchmark 10-year notes have come back and are essentially at this year.

Nevertheless, any consistent drop-off in foreign demand could have lasting consequences on the US’s ability to finance itself cheaply, particularly in light of Trump’s ambitious plans to boost infrastructure spending, cut taxes and put “America First".

In December, Japanese investors reduced their investments in US debt by 2.39 trillion yen ($21.3 billion) after a smaller pullback in November. While only a fraction of Japan’s $1.1 trillion of holdings, they were the first back-to-back declines since the start of 2014. China, which owns just over $1 trillion of Treasuries, has been selling since May. Its holdings are at a seven-year low.

Last quarter, Japanese investors who hedged all their dollar exposure in Treasuries suffered a 4.7% loss—the biggest in at least three decades. The same thing happened in Europe, where record currency-hedged losses also stung euro-based buyers.

Combined with the unpredictability of Trump’s tweet storms, interest-rate increases in the US could further sap overseas demand.

What’s more, central bankers in Japan and Europe are still experimenting with monetary policies that may benefit bond investors locally.

Right now, it’s just “much easier to stay home than go abroad", said Shyam Rajan, Bank of America’s head of US rates strategy.