A one-two punch, centered on continued doubts about President Donald Trump’s Wall Street-friendly agenda and hawkishly interpreted comments from global central bankers, knocked investors around, recently sparking a surge in yields and sharp swings in currencies.

Global government bond yields, which move inversely to prices, and the euro were jolted higher, putting pressure on the U.S. dollar on the heels of statements from European Central Bank President Mario Draghi, whose remarks were taken as a suggestion that the ECB may be inclined to wind down its balance sheet as European growth picks up. Those comments were followed by similarly upbeat utterances from Bank of England Gov. Mark Carney

Read:What happened to Mario Draghi’s silver tongue?

Combined with expectations that the Bank of Japan may be on a similar footing, a world-wide effort to normalize monetary policy removes a longstanding safety net from a stock market bull-run that is in its ninth year and comes amid mounting concerns that Trump’s pro-growth agenda won’t soon become a reality.

On Thursday, long-dated bond yields were looking at their biggest weekly gains since the period ended March 3, according to WSJ Market Data Group. In other word words, bonds prices were getting slammed. The 10-year Treasury note TMUBMUSD10Y, 0.657% which was high as 2.29%, up about 14 basis points on the week, while the 30-year bond TMUBMUSD30Y, 1.403% , also flirting with its steepest yield climb since March, has punched higher by more than 11 basis points so far this week.

Meanwhile, against the euro EURUSD, +0.00% , the dollar was down 2% on the week.

Those are sizable swings, and many of those moves occurred over the course of 48 hours, highlighting the potential for markets to abruptly experience a so-called “taper tantrum “on the threat of two legs of economic and market stimulus being suddenly removed or delayed.

“As I believe the main factor in driving market multiples to historically high levels was QE, ZIRP and NIRP, then yes, the reversal will have major implications for markets and volatility.” Peter Boockvar, chief market analyst at The Lindsey Group, told MarketWatch, referring to quantitative easing, and zero and negative interest-rate policies that prevailed over the past several years as global central banks sought to breathe life into anemic economies in the aftermath of the 2008-’09 financial crisis.

Trump’s promises of fiscal stimulus, including tax cuts, deregulation and a boost to infrastructure spending of about $1 trillion, had underpinned the Dow Jones Industrial Average DJIA, +1.33% , S&P 500 index SPX, +1.59% and the Nasdaq Composite Index’s COMP, +2.26% recent record-setting rallies.

However, divisions within the Republican party over a health bill intended to overhaul the Affordable Care Act, aka Obamacare, has cast doubt about the president’s ability to enact other elements of his ambitious legislative agenda.

That is bad news for markets that have relished a protracted period of ultralow rates amid global growth that is demonstrating signs of improvement but isn’t exactly running full tilt, by some measures.

“It looks like the tightening era has begun, though markets are far from having come to grips with it,” financial blogger Wolf Richter writes in a recent report, cited by Victor Reklaitis in MarketWatch’s Need to Know column.

Notably, readings of inflation remain lower than the Federal Reserve and other central bankers are expecting. Still, Fed Chairwoman Janet Yellen has justified this month’s quarter-point rate increase, by describing inflation that has fallen below the central bank’s 2% target as a “one-off.”

Sovereign bond-market investors, however, haven’t agreed with that assessment—until recent trade. Sluggish inflation implies that the economy is improving and lifting benchmark rates are one tool the Fed can use to prevent the economy and market from overheating. High inflation is anathema to bond investors as it erodes the value of fixed-income assets.

Bets that the Fed is wrong-footed on its inflation estimates have been one factor weighing on yields, despite rate increases that should give them a nudge. Other factors include worries about the potency of the U.S. economic recovery and investors turning to U.S. Treasurys relative to other lower-yielding sovereign paper.

A Thursday note from Bank of America Merrill Lynch strategists makes the case that investors are complacent about the potential impact of tighter policy, and specifically the Fed’s reduction of its $4.5 trillion balance sheet.

“We think the market is complacent on the stock effect of the Fed’s balance sheet decline,” wrote B.of A. analysts led by Shyam Rajan.

The cocktail of Fed tightening and unfulfilled fiscal-stimulus promises also had led to an odd dynamic between bonds and equities. When investors are at their most cautious, bond prices are usually expected to rise, pushing down yields, while stocks are expected to fall.

Instead, bond yields have been falling while stock prices rise.

J.J. Kinahan chief strategist at TD Ameritrade said the tug of war between the pair of assets has left stocks in the drivers seat—at least for now.

“It seemed as if the bond market did not believe the stock market and these recent moves hint that the more natural relationship is coming to bear,” he said. Although Thursday’s market downdraft, underscores how fleeting victory can be.

To return to that level of normalcy may have at least one clear result: a rebirth of volatility and sharper daily moves after a period of complacency, as measured by the CBOE Volatility Index VIX, -7.47% , or fear gauge. On Thursday, the fear gauge notched its worst daily drop since May 17, when it fell 46%.

Kinahan said the real catalyst for the market will be coming corporate earnings, which may provide more concrete backing to the optimism that has lifted markets to rich valuations.

“If we have another good earnings season, it is going to be very difficult to keep the stock market down,” Kinahan said.

Until then, its seems that investors will be focused on the interplay of fiscal and monetary stimulus

Check out:MarketWatch’s snapshot of Wall Street