Although we don't believe in timing the market or panicking over daily movements, we do like to keep an eye on market changes -- just in case they're material to our investing thesis.

Stocks opened higher this morning, with the S&P 500 and the narrower, price-weighted Dow Jones Industrial Average (DJINDICES:^DJI) up 0.5% and 0.66%, respectively at 10:15 a.m. EST.

Yesterday morning, in the run-up to niche automaker Tesla Motor's (NASDAQ:TSLA) third-quarter results, I wrote, "While I think individual investors are unlikely to come out ahead by trying to 'game' the earnings, betting on a beat or a miss, I think there is every chance that the stock will be volatile in the wake of the release, during today's after-hours session and tomorrow."

Once in a while, I get things right. That's certainly the way things are playing out: The shares were down 12.3% at the end of yesterday's after-hours session, and the same loss is largely reflected in this morning's trading.

On the bright side, Tesla Motors did beat analysts' expectations for a breakeven quarter with a $0.12 per-share profit (ex-items). Furthermore, vehicle gross margin excluding zero-emission vehicle credits (the profit margin per car, roughly speaking) rose to a record 21% -- and better yet, the company says it's on track to achieve 25% in the current quarter.

However, the fourth-quarter guidance that the company provided in its shareholder letter may have soured the market on the stock -- specifically, the section in which the automaker said: "We expect our non-GAAP profitability to be about consistent with Q3. ... Free cash flow is expected to be close to breakeven." In the third quarter, Tesla generated $26 million in free cash flow.

Worse still, investors who were looking to 2014 for any significant cash flow will have been disappointed: CEO Elon Musk told investors and analysts on the earnings call that the company expects to generate a bit of positive cash flow next year. Remember, folks, a company's valuation is ultimately tethered to expected future cash flows, and these cash flows may be starting to look a long way off to Tesla shareholders. Meanwhile, you hardly need a telescopic lens to catch a glance of the stock's valuation -- at 185 times estimated earnings per share over the next 12 months, it looms very large indeed.

Tesla Motors' stock has had a stunning run in 2013, up 400% as yesterday's close. Elon Musk recently told CNBC that the market "is being very generous [with Tesla's value]." It looks like we may be testing the limits of that generosity as the market adopts a more reciprocal "show me" attitude toward Tesla's results.