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The stock market has gone more than a year without a 5% pullback, but a correction isn’t the only thing missing in action. What’s also baffling is the mystery of disappearing inflation.

A correction, like your misplaced car keys, will turn up sooner or later. But inflation’s absence has become especially glaring after the long, loud drum roll anticipating its appearance—what with our economic expansion entering its ninth year, a well-publicized synchronized global recovery, the Trump administration’s promise of fiscal fireworks, and tightening policies by central banks from the U.S. to China. Yet the core consumer price index eked out a year-over-year increase of just 1.7% in June, the slowest in two years. Stripping out shelter costs, core inflation grew just 0.6%, the most sluggish rate since 2004. Personal-consumption expenditures are growing at a 1.4% pace, shy of the Federal Reserve’s 2% target.

You may think it’s perverse to wish for inflation, and life’s necessities—a nice house, stiff drinks, Orlebar Brown swim trunks—seem only to get more expensive, not less. But stable inflation lets businesses hike prices of the goods and services they sell, and raise wages. It’s no coincidence the labor market is tight and unemployment is down to 4.4%, but wages are growing at a glacial pace of about 2.5%.

For a stock market braving new peaks—the Standard & Poor’s 500 index just snagged its 27th record high of 2017—weak inflation reinforces concerns that the Fed is tightening even when our slow-growth, low-interest-rate economy is going nowhere fast.

Why does inflation keep falling short of expectations? For one thing, “excess debt encourages saving, not spending,” notes Michael Hartnett, Bank of America Merrill Lynch’s chief investment strategist, who cites data from the Institute of International Finance showing global debt hitting an all-time high this year of $217 trillion, roughly 327% of global gross domestic product. Next, he adds, aging populations also tend to save more and spend less, and even though demographic trends here are sprightly compared with, say, Japan and Europe, over the past decade the annual growth in the U.S. working population has shrunk from 1.3% to just 0.5%.

On top of that, automation, robots, and artificial intelligence are pressuring human wage expectations. Technology disruption may one day prompt policy changes that could include, for example, taxing robots or levying higher taxes on Silicon Valley profits, Hartnett notes. For now, he says, “corporations continue to emphasize cost-cutting over risk-taking, and wide swaths of the labor market see that their ability to maintain wages and incomes are under enormous threat from technology.”

The worrisome thing is how inflation seems to have befuddled central bankers. Fed chair Janet Yellen has said that weak recent inflation readings are merely “transitory,” and she pointed to a price war in mobile phone services and a decline in prescription drug prices as momentary inflation depressants.

But the Fed has brushed aside feeble inflation as transient year after year after year, and still inflation has yet to catch up to the Fed’s 2% goal. Back in 2015, for example, Yellen said inflation was held back by collapsing oil prices and weakening imports in the face of our strong dollar. Well, energy prices have since rebounded from early-2016 depths, and the dollar just declined to a 30-month low against the euro. But there’s always something else, and new culprits springing forth to hold inflation hostage.

IN THE COMING MONTHS, expect the Fed to be extra sensitive to any whiff of faltering growth.

With inflation already below target, the Fed has less cover to continue its painstakingly telegraphed plan to raise rates and shrink its balance sheet. At first, this will cheer a market accustomed to the addictive fix of easy money. But the Fed has fewer tools at its disposal if growth starts to flag, what with interest rates already low. On the other hand, if inflation were to start climbing, financial markets—which are pricing in only a 39% chance of one more rate hike through year end—just might be startled.

It’s a good thing the economy is growing, but how much of that growth is already factored into rising stock prices? Companies are on track to report second-quarter profit growth of 9.6%, compared to 15.3% in the first quarter. So far this earnings season, companies that beat targets have eked out average gains of 0.6% in the first session after reporting, notes Bespoke Investment Group. But companies merely meeting their forecasts slipped 2.7%, while those missing their marks were drubbed 4.6%.

In June, retail sales grew 1.2% year over year, down from 2.1% in May, and it remains to be seen if Washington can deliver the promised tax cuts and fiscal stimulus before growth slows further. In a July survey of global fund managers conducted by BofA Merrill Lynch, the percentage who expect faster global growth over the next 12 months shrank to 38%, down from 62% back in January. Profit expectations are rolling over as well. Only 41% see profits improving over the next 12 months, the lowest since the election and down from 58% in January.

Against this backdrop, we’re crowding back into what we fear could become scarce. Big tech stocks, after a brief bout of profit-taking in late June, have regained their swagger and market leadership and are up 23% this year. Growth stocks in the S&P 500 nudged back ahead of their value counterparts to reach another all-time high and are up 15.8% this year, compared with 4.5% for value stocks. Inflation may be in retreat, but in the stock market, prices seem only to march higher.