Source: Lumber Liquidators.   

Last week was brutal. You have to go back four years to find the last time the major market averages fell as hard as they did this past week.

Not every stock took a dive, though. Some bucked the trend, and a few of those actually delivered some pretty meaty gains for their investors. In fact, three of this year's biggest losers -- Lumber Liquidators (LL -3.80%), LifeLock (LOCK), and zulily (NASDAQ: ZU) -- bounced back with double-digit percentage gains on the week.

Let's take a closer look at what drove the companies higher, and how much ground they still need to make up to get in the black for 2015.

Lumber Liquidators: up 10% for the week, down 77% in 2015
Things haven't been the same for the hardwood retailer since 60 Minutes singled it out in February, calling into question the unacceptable and potentially toxic levels of formaldehyde in its Chinese-sourced laminates. The stock has moved lower in all but one month this year.

It caught a break this week, even with 60 Minutes running the piece again last week with an editorial update. The reversal happened after Cantor Fitzgerald upgraded the stock. Encouraged by the retailer's long-term outlook on gross margins after touring a store with senior management, analyst Laura Champine upgraded her rating on the stock from "hold" to "buy," boosting her price target from $15 to $18 along the way. Now, $18 may seem pretty ho-hum for a stock that was trading in the triple digits two years ago, but it's not too shabby for Lumber Liquidators stock, which kicked off the week in the low teens.   

LifeLock: up 10% for the week, down 56% in 2015
The leading identity-theft monitoring service lost more than half of its value last month, after the the Federal Trade Commission accused LifeLock of violating a 2010 order to refrain from deceptive marketing claims. The FTC also claims that LifeLock isn't doing an adequate job of protecting the sensitive data of its subscribers. As you can imagine, this is not the kind of publicity a company that prides itself on protecting identities likes to receive. It warned in its late July earnings call that the unwelcome attention would probably result in difficulties attracting new members and retaining existing ones. 

There was no public news to drive LifeLock higher this week, unlike Lumber Liquidators and Zulily, where the catalysts were clear. However, the stock had fallen so far in recent weeks that a dead-cat bounce isn't a surprise. 

Zulily: up 42% for the week, down 24% in 2015
If you have a strong brand and a growing business, it's often just a matter of time before a buyout bails out a freefalling stock. That's how things played out for Zulily, the online retailer that initially specialized as a deep discounter on clothing and accessories for moms and children.

QVC's parent company stepped up last week with a cash-and-stock proposal to acquire Zulily in a deal that was originally valued at $2.4 billion. The deal should close in a few months, and even though Zulily will go out as a busted IPO -- it went public at $22 two years ago -- it's going out on a high note as one of last week's biggest gainers.