BEIJING, Dec. 8 - As China's stock market continues a record-breaking streak that includes a flux of mom-and-pop investors, some words of caution are in order.

It's not that one of the world's worst-performing markets does not deserve a rally or two, but even a "bull market" does not adequately describe the frenzy at the Shanghai and Shenzhen exchanges. In the last 11 trading days, two key stock indexes climbed around 20 percent, with the biggest one-day turnover hitting 1 trillion yuan (162 billion U.S. dollars).

Granted, the rising tide is not completely unfounded. All playing their part, the central bank recently had a considerable injection of liquidity as well as a benchmark rate cut, a stock trading link between Shanghai and Hong Kong was established, housing and high-yield investment markets both cooled, and A shares were on offer for cheaper price.

But all these factors appeared insufficient to put the stocks on fire. For example, the underwhelming Shanghai-Hong Kong Stock Connect proved less exciting than many had expected.

More broadly, the Chinese economy is still - painfully - adjusting to the so-called New Normal where growth will slow further, with Monday's trade numbers showing the latest weakening signs: exports and imports in November fell sharply below expectations.

But the big picture supposedly did little to affect the thinking of retail investors, who have recently been flooding brokerages and pushing the indexes to new highs.

For individual investors, who significantly outnumber institutional investors in domestic exchanges, greed now appears to triumph fear, with extraordinary, if not maniacal, numbers of new account openings and purchases that had not been seen for years.

Also unseen was the enormous role of leverage in this rally, as introduction of margin financing enabled investors to buy shares with borrowed money. Outstanding margin position is now around 850 billion yuan, more than double the figures reported at the end of June. Should trends reverse, the volatility must not be understated.

From a longer perspective, a sustained bull market is only a matter of time as China's deepening reform and opening-up is now on fast track to provide results.

The problem with a momentum market, however, is that one can't tell when the tide will turn. Therefore, it is necessary to ring some bells now as the red-hot market is rocketing a bit too fast.