By Steven Russolillo

Amazon shares getting slammed following disappointing 4Q results reported late yesterday. The reaction nearly mirrors the sharp drop the stock suffered about three months ago after a downbeat 3Q report.

The story remains the same for Amazon: the online retailer continues to invest heavily in its various businesses. Analysts keep questioning whether the company's revenue growth will be sustainable enough to more than offset rising expenses.

The company's fourth-quarter revenue jumped 35%. But operating expenses rose 38%. Overall quarterly profit slumped 57% from a year ago.

"We feel very good about the investments that we're making," Amazon CFO Tom Szkutak said on a conference call. "We're still experiencing very high growth."

Wall Street isn't so sure. The stock is down more than 9% and has slumped about 28% since peaking in mid-October. Collin Gillis from BCG Partners says investors need to be aware of several negative aspects of Amazon's business.

Investors in Amazon should be concerned over the lack of visibility the company gives into critical parts of its business including: a) number of kindles sold, b) the profitability (if any) of the hardware, c) the economics of its Prime program, and d) the revenue and profitability of its digital books, music and movies business. We do not suggest paying an ultra premium valuation for shares of Amazon given the lack of information in critical parts of its business.

Evercore Partners analyst Ken Sena is also concerned, although he hedges his view by saying Amazon's long-term platform advantage should continue to outpace competitors. That said, he's pretty cautious on the stock over the short term.

We concede that this current investment cycle is likely to remain rocky for investors until Amazon can offer some end in sight. Therefore, despite Amazon remaining an attractive long-term buy in our view, we are incrementally more cautious near-to-medium term.

A hat tip also goes out to Dow Jones editor Kevin Kingsbury who points out analysts are generally eager to tell investors to "buy the dips" after a company reports disappointing results and its stock slumps.

That isn't the general consensus today among the Wall Street community.

"We don't think it makes sense to buy Amazon on weakness," says Trip Chowdhry of Global Equities Research. "Amazon is entering a period of secular headwinds."

Amazon shares fell 13% in October the day after it reported 3Q earnings, which was the stock's single biggest percentage drop in its history. After Amazon's 4Q results, the stock is experiencing a similar decline.