Dropping the most was auto parts company U.S. Auto Parts Network Inc., which saw shares dip 42 percent for the week. The Carson-based company reported poor forth quarter earnings; shares tumbled to $2.70.

Also dipping due to poor earnings was Los Angeles-based outsourcing services provider PeopleSupport Inc., which shed 24 percent to $8.63.

Finally, Santa Monica-based Anworth Mortgage Assets Corp. also suffered from poor earnings. Shares in the real estate investment trust lost 22 percent to $4.83 for the week.

On the way up was United Online Inc., which saw its shares gain 11 percent after an investment firm initiated coverage on the Woodland Hills-based company. Shares closed the week at $10.85.

Benefiting from unexpectedly good fourth quarter earnings was Van Nuys-based aluminum wheel manufacturer Superior Industries Inc. which saw shares gain 11 percent to $19.85.

Finally, Long Beach-based health care properties owner HCP Inc. gained nearly 9 percent to $29.97 after the health care-focused real estate investment trust announced it had sold a portfolio of its properties.