Whether an earnings report, speculation or some other force has driven climbs, some stocks that slogged through the end of 2014 have jumped this year. Netflix, for instance, closed 2014 at about $340 per share, but after enjoying its best day in a year on Wednesday, the stock now sits at about $409 per share.

Another 2014 laggard, Amazon, gained nearly 3 percent on Wednesday, while eBay surged almost 3 percent in after-hours trading following a mixed quarterly earnings report. CNBC's "Fast Money" traders won't necessarily jump on the reversal trades immediately, though.

Netflix jumped more than 17 percent on Wednesday. The stock may have some room to move upward, but it will likely start falling around $420 per share, said trader Brian Kelly.

"I would not tomorrow morning get out there and start buying Netflix. I would give it a week or so just to see how it settles in," Kelly said.

Read MoreHere's how Netflix nailed it

To gauge where the stock goes, investors should watch the streaming media company's international growth, trader Pete Najarian noted. If Netflix keeps on its expected international expansion trajectory, the stock could hit $500 per share, he said.

He added that the stock would start to look appealing if it fell back below $400 per share.

Ebay on Wednesday reported weaker-than-expected guidance and announced it would cut about 7 percent of its workforce. But shares surged in extended trading ahead of the company splitting its marketplace and PayPal businesses and a Carl Icahn-approved board member joining the e-commerce giant.

Read MoreEBay CFO: It will get worse before it gets better

While the business may not be in dire straits yet, "Fast Money" traders said they would hesitate to make a play in eBay until shares slipped below $50 per share from their current level around $55 per share. Even then, Kelly would look at the company mainly for the PayPal spinoff.

"If you break through $50 on eBay's stock then I'm going to start to get interested," Kelly said.

Najarian noted that there are reasons to own eBay beyond PayPal. Growth in new active marketplace users looked promising, he said.

"eBay might surprise people to the upside," said trader Guy Adami.

Traders expressed more skepticism over Amazon's jump. The stock ended around $297 per share on Wednesday, and a price around $300 per share "reflects optimism" that Amazon will eventually rein in its spending, said trader Karen Finerman.

"I don't know if [Amazon CEO] Jeff Bezos cares where his stock trades," Finerman said.

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Disclosures:

Karen Finerman

Karen Finerman is long BABA, BAC, C, CVS, FINL, FL, FRO, GOOG, GOOGL, KORS, M and MTW. She is short DIA. Her firm is long AAPL, ANTM, BAC, PLCE, C, CMLS, CVS, DIS, DRI, FINL, FL, GOOG, GOOGL, GPS, HTZ, IBB, JPM, KORS, M, MTW, SUNE, URI, WFM and XBI. Her firm is long calls SUNE and C spreads. Her firm is short USO, DIA and IWM. Karen Finerman is on the board of GrafTech International.

Brian Kelly

Brian Kelly is long BTC=, Gold, US Dollar, HYG puts and TWTR call spreads. He is short EWA, EWG, EWQ, EWZ, EWH, EWW, HGH5, Yen, Australian dollar, British pound and Canadian dollar.

Pete Najarian

Pete Najarian is long AAPL, BABA, BAC, CSX, DB, EBAY, INTC, JPM, KKR, KO, LLY, LOCO, MRK and ODP. He is long calls AA, AAL, ABX, APD, ARCP, BABA, BIC, BBRY, CY, DAL, DD, DNKN, EBAY, EWG, GS, GT, HCBK, IAG, ISIL, JPM, MAS, MCD, MS, PEP, RF, SPY, UAL, VGK, WU and XLF. Today, he bought EWG calls and VGK calls.

Guy Adami

Guy Adami is long CELG, EXAS and INTC. Guy Adami's wife, Linda Snow, works at Merck.