The latest batch of government data showed a stunning drop in growth in China's financing activity in July—a troubling sign in an economy where debt has become critical to expansion. Total social financing, the broadest measure of lending, expanded by 273 billion yuan ($44 billion) from June, the slowest since the collapse of Lehman Brothers.

The numbers were enough of a shocker—and possibly something of an anomaly—that the central bank felt it necessary to accompany the data release with an unusual written statement explaining that its policy stance hasn't changed. It said July's slump was explained by higher-than-normal lending in June of nearly 2 trillion yuan, among other factors. July has historically been among the slowest months for credit creation. The statement hinted that lending in August has gotten off at a more normal pace.

Another explanation is that the central bank's efforts to curb lightly regulated shadow financing are having an effect. Bankers' acceptance bills, a form of off-balance-sheet lending used by banks, fell sharply. A crackdown on commodity financing in the wake of a scandal in the northeastern port of Qingdao may also be at play. The central bank, which represents a camp in the government that advocates weaning the economy off debt-fueled growth, may find itself under pressure to loosen the taps should the current formula fail to deliver ample growth.

The more troubling conclusion is that despite ample liquidity in the financial system, borrowers just aren't in the mood. Activity data seem to support this. The critical real-estate market continues to slide: Transaction volumes, which had shown signs of recovering, declined at a faster rate in July. They were down 18% from a year earlier, compared with a 5% drop in June. Electricity production grew just 3.3%, compared with 5.7% in June. Retail sales, including car sales, also grew more slowly in July.

It's almost never a good idea to get too bent out of shape by one month's data. But the message from July seems to be that the recent pickup in China's economy may be more short-lived than some had hoped. It also means meeting Beijing's yearly growth target of 7.5% will be harder to achieve. More government stimulus seems likely.