The first week of earnings season was more than kind to the S&P 500 Index (^GSPC -0.10%), and the benchmark ended at another all-time closing high on Friday. It didn't hurt that the Fed promised to continue buying $85 billion in bonds each month until the economy gets on better footing, but corporate profits were strong on their own merits. Wall Street closed the day looking forward to more results next week, with the S&P adding five points, or 0.3%, to end at 1,680. That said, negative developments in three of the index's components weren't easily ignored, and shareholders had little choice but to sell them off.

Firstly, the United Parcel Service (UPS 0.68%) saw shares tumble 5.8% as the mail-delivery service reduced its second-quarter and full-year outlook. UPS officially reports second-quarter results on July 23, but it went ahead and told markets not to expect anything spectacular; the company's looking for earnings between $4.65 and $4.85 per share for the year, compared to Wall Street estimates of nearly $5.00 per share. Not only that, but UPS sees the downtrend to continue into the foreseeable future.

In a textbook example of a situation where you can expect nothing but a steep stock sell-off, Boeing (BA 0.68%) shares fell 4.7% after one of its 787 Dreamliners caught fire at London's Heathrow Airport. Luckily, no one was injured, and the plane was unoccupied at the time. Sound familiar? That's because a fire broke out on a Dreamliner back in January at Boston's Logan Airport, an event that caused the model to be grounded for months, as technical and safety tweaks were made. In short, today's events amounted to downright hellish deja vu for shareholders.

Lastly, iron ore and coal miner Cliffs Natural Resources (CLF 0.50%) shed 3.5% Friday. It's a shame, because the stock had been on a tear this week, a much-needed bullish run investors have rarely seen in the last year, as the market cap took a 60% haircut. The struggling miner announced its CEO, Joseph Carrabba, will be stepping down at the end of the year, along with the immediate departure of its global operations chief.