Investors are fleeing Europe.

Fund managers are pulling cash out of European equity and debt markets in response to concerns about the continent’s fractious politics, ultralow interest rates and weak banks, and relentless economic malaise.

Investors have sold exchange-traded funds tracking European shares for nearly 15 weeks—the longest stretch since 2008—according to UBS Group AG. Meanwhile, annual net outflows from eurozone bonds were running at over half a trillion euros as of the end of March, according to a Pictet Wealth Management analysis of data from the European Central Bank. That is happening as investors are turning away from Europe’s growing pool of negative-yielding debt.

The money is finding a home in places from U.S. Treasurys to emerging economies, helping to push up prices in those markets.

Just last year, Europe was a top pick by global fund managers as it recovered from the sovereign-debt crisis of 2010 to 2012. The current retreat shows that this rehabilitation has faded, and fast.

“It’s a one-way flow out of Europe,” said Ankit Gheedia, equity and derivatives strategist at BNP Paribas SA . “You buy something that doesn’t give you a return, you sell.”

Last year, ECB monetary stimulus and a fledgling economic recovery brought investors back to Europe after they fled during the eurozone debt crisis. The Stoxx Europe 600 gained 6.8% in 2015, while the S&P 500 lost almost 1%.

Now people are leaving again.

In recent weeks, investors have been selling equities around the world over concerns about the global economy. But the selling in Europe has been particularly pronounced.

Funds have sold around $22.6 billion worth of ETFs that track European equity since March, which is equivalent to roughly 9.4% of the total held of these investments, according to Mr. Gheedia.

Meanwhile, global fund managers’ allocation to eurozone equities dropped to 17-month lows in May, according to a survey by Bank of America Merrill Lynch. When prospects seemed sunnier last year, a net 55% of fund managers favored the region.

This is already taking a toll on European markets. The Stoxx Europe 600 is down nearly 8% this year, compared with a roughly flat S&P 500.

Banks are Europe’s worst-performing sector, having fallen nearly 19%.

Investors are concerned that negative interest rates are eating into the sector’s margins, while lenders in Southern Europe continue to grapple with bad loans.

That could have a knock-on effect on a continent where companies rely on bank lending for around three-quarters of their funding needs. Banks also make up an outsize chunk of local equity markets.

Investors’ concerns over banks are already being borne out after a poor set of results in the most recent earnings seasons.

The downbeat news about profits wasn’t just from banks. Overall, that earnings season has deepened investors’ doubts about profitability in Europe.

“After 10 years of zero earnings growth in Europe, investors are becoming increasingly pessimistic,” said Karen Olney, a European equity strategist at UBS. “Year after year investors waited for the big bounce in earnings, and year after year they were let down.”

The region faces a number of key political tests that could further destabilize its recovery and keep investors on the sidelines.

On June 23, the U.K. will vote on whether it should remain part of the European Union. If Britain does vote to leave, that could roil financial markets across Europe as a result of concern that other countries may follow.

“Unless you have a strong view that Brexit is not going to happen, [Europe] is a risky play,” said Luca Simoncelli, investment manager at Unigestion, which manages $19.5 billion in funds.

Bond investors are also leaving Europe, but for different reasons.

The ECB’s stimulus measures, including cutting interest rates below zero to boost sagging inflation, have dragged down the yield on eurozone government bonds. Yields fall as prices rise.

Roughly €3.5 trillion ($3.9 trillion), or 54%, of these securities trade at a negative yield currently, according to Bank of America Merrill Lynch.

That is pushing investors to look elsewhere for returns, including in emerging markets and U.S. Treasury bonds, analysts say. With the 10-year German bond yielding 0.181%, the 1.85% yield on the 10-year Treasury bond looks a lot more appetizing.

“We’ve seen a lot of flows into anything with a positive yield,” said Steve Thompson, senior client-portfolio manager at Invesco Fixed Income.

Not everybody is giving up on Europe.

Sustained selling across eurozone assets, as well as further gains in the dollar, could push the euro lower and boost the competitiveness of European exporters. Some analysts also point out that the eurozone’s economy picked up in the first three months of the year.

If British voters elect to stay in the EU, as current polls suggest they will, that could also trigger a  relief rally as those investors who held back start to buy again, analysts say.

The selloff has brought valuations down compared with the U.S., which could also tempt bargain hunters. Companies in the Stoxx Europe 600 trade at a 12-month forward price/earnings ratio of 14.8, compared with 16.5 for the S&P 500.

But many remain skeptical about the region’s prospects.

“On a relative basis, [Europe] appears to be a little bit cheaper than the U.S., but when you look at underlying growth, you can certainly argue it’s cheaper for a reason,” said Michael Mussio, managing director at FBB Capital Partners, a U.S.-based wealth management firm.