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.

For most stock market investors, today was a good day, with the Dow and S&P 500 rising to new record highs. But even with many stocks joining in the bull-market rally, Mechel OAO (NYSE:MTL), Chegg, and Einstein Noah Restaurant Group (UNKNOWN:BAGL.DL) got left out, falling double-digit percentages even on the favorable market day. Let's examine what happened to these companies to send their stocks dropping today.

Russian mining and steel company Mechel dropped more than 23% as investors in the debt-ridden company fear that low prices for steel and coal will prevent it from managing its debt load well. Mechel has asked creditors for time to get itself looking healthier financially, and the company said that it expects negotiations to be done by the end of the month. Even if it gets its debt restructured, though, Mechel won't recover fully until the hard-hit commodities market bounces back from its huge setbacks in recent years.

Newly public Chegg matched Mechel with a 23% decline of its own, posting a big first-day decline after shares were priced at $12.50 in its IPO. The company's business model involves renting textbooks to college students, seeking to help its customers avoid the expensive proposition of buying new books each semester only to immediately sell them back at discounted prices to used-book buyers after the class ends. As the bull market progresses, you can expect to see similar disappointments in IPOs of marginal companies with little or no track record of profitability.

Einstein Noah fell 10% after announcing that 2.5 million shares were sold in a secondary public offering at $17.25. The company, though, didn't raise any capital from the sale, which solely involved shares held by Greenlight Capital. Investors likely didn't appreciate the selling pressure that resulted from the offering, but even more damaging might have been the implied loss of confidence from David Einhorn's hedge fund company.