Options Action
Options Action

Mystery investor places massive bets on eBay

Did Icahn buy a bunch of eBay calls?
VIDEO1:4501:45
Did Icahn buy a bunch of eBay calls?

Ebay stock options have become increasingly active in the past three months, as a series of very large bullish bets indicate substantial hedge fund interest in the stock.

Over the course of four major options trades, 159,000 calls were bought, for a total outlay of nearly $18 million in premium. And as traders—or one big trader—snatched up the calls, open interest in the stock options skyrocketed.

"All of a sudden, we see this huge spike in interest, and it obviously has to do with those big call purchases," said Dan Nathan of RiskReversal.com. "That's pretty sizable—that's a big player."

Many of the trades appeared to target eBay's January earnings announcement. The company did end up reporting a strong fourth quarter, but that news was overshadowed by the revelation that Carl Icahn had taken a stake in the company and planned to use activism to spur change.

Despite that, the stock has lost ground from its trading level before those announcements.

(Read more: EBay dismisses Icahn proposal to spin off PayPal)

"The options activity equated to buying a rumor, and the action after the news was a classic 'sell the news,' " Nathan said.

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However, among the large trades was the November purchase of 50,000 July 62.50/65 call spreads, indicating that the trader expected the stock to rise to $65 by July expiration. That trade bore a similarity to the purchase of 10,000 January 2015 52.50/65 call spreads, which make their maximum profit if eBay shares rise to $65 by January 2015 expiration.

These trades could speak to an interest in the stock in the slightly longer term.

"I would take this kind of options trading activity to mean that an informed market participant might be finding a near-term catalyst to propel it higher," said Mike Khouw, primary strategist at Dash Financial.

Yet partially because the options trades show a conviction that the stock will trade somewhat—rather than massively—higher, Icahn's fingerprints do not appear to be on them.

Many believe that the stock—which has gone nowhere as the market soared over the past year—is a decent value, Khouw said.

"But if it's underpriced," he added, "that's not necessarily a good reason to get long."

(Read more: PayPal is stronger staying with eBay: EBay CEO John Donahoe)

That's why Khouw believes there was one major player behind these trades who has a specific catalyst in mind.

"I'm just not sure that this tells me just what that catalyst is," he said.

—By CNBC's Alex Rosenberg. Follow him on Twitter: @CNBCAlex.

Follow the show on Twitter: @CNBCOptions.