The stock market closed out the week on a sour note today, as selling in hot biotech names again caused negativity to spread to other parts of the market. All 10 sectors finished lower Friday, led by health-care's whopping 4.5% tumble. While consumer sentiment this month notched its highest reading since last July, Wall Street paid no notice, and the Dow Jones Industrial Average (DJINDICES:^DJI) lost 143 points, or 0.9%, to end at 16,026.

The Dow doesn't play host to any flash-in-the-pan growth stocks; the 30 "blue chip" components of the index are all household names, famed for their steady returns and massive size. But even these titans of American industry looked risky Friday, as JPMorgan's miserable first-quarter earnings made ripples through the market. Home Depot (NYSE:HD) investors were justifiably spooked by JPMorgan's soft mortgage business, and shares of the home improvement retailer dropped 1.4%. Loan origination at the country's biggest bank fell from $53 billion a year ago to just $17 billion in the first quarter. If real estate falls off too rapidly, so will Home Depot's business, which relies heavily on home renovations and remodeling.

Source: J.C. Penney website

Shares of clothing retailer J.C. Penney (OTC:JCPN.Q) also sold off today, though the 9.6% pullback put Home Depot's to shame. The future of the business, while much improved from just three months ago, remains hazy; J.C. Penney's liquidity is still a focus of extreme investor concern as it tries to execute a turnaround. Although we've started to see evidence of that turnaround in increasing same-store sales, cutting costs is still a top priority, and that could mean closing more stores. Mall developer and REIT CBL stated as much today, saying it expected further closures at J.C. Penney in the future. 

Finally, Sirius XM Holdings (NASDAQ:SIRI) finished as a standout stock today, adding 1.9%. The satellite radio leader enjoyed the benefit of a debt upgrade, as Standard & Poor's and Moody's both upgraded a tier of its debt to "investment grade." In a press release, Sirius XM's CFO David Frear touted the upgrades as meaningful to the company because the investment-grade debt will "no longer constrain our share buyback activity." SiriusXM Canada also renewed an agreement with Volkswagen and Audi that ensures Sirius systems will continue to come factory-installed in new cars.