The Rydex CurrencyShares Euro ETF (NYSEArca: FXE) was at the center of large creations and redemptions over the past two trading sessions, as a large sum moved into the long euro-dollar ETF on Friday, only for two-thirds of that sum to come flying back out the following Monday.

A total of $357.4 million flowed into FXE on Friday, a 72 percent spike that lifted total assets in the ETF to $851.2 million. On Monday, the ETF suffered outflows of $247.7 million, which cut assets by 29 percent to $606.2 million, according to data compiled by IndexUniverse.com.

Traders and strategists aren’t sure who was behind the in-then-out activity on FXE, but reckon it was probably one or two big players who were suddenly concerned about anxiety coursing through financial markets yesterday that Ireland and Greece might not be able to meet debt obligations. The two countries—Greece in particular—were at the center of Europe’s sovereign debt crisis earlier this year.

“If you look at the recent trend of the euro versus the dollar, the euro has been gradually strengthening against the dollar,” said Paul Weisbruch, an ETF trader at Street One Financial in King of Prussia, Pa., in a telephone interview. “They probably got spooked by headline risk and exited the position quickly.”

Recent Spiking

Volume on FXE trade has been spiking recently. It was almost six times its average volume over 30 days on Friday and about 4.5 times that figure on Monday, according to data compiled by IndexUniverse.com.

“It spurred a lot of volume, a lot of creation/redemption activity and, in a way, it kind of reinforces the beauty of ETFs. You can establish a large position and exit it without any lockup period. What did they pay, except for the commissions on the trade, really?” Weisbruch said.

Concerns about Europe were stoked by comments from Pimco’s Mohamed El-Erian. The chief executive officer of the world’s biggest bond fund manager wrote in ft.com’s ftalphaville that measures of solvency risk to peripheral European countries such as Ireland or Greece were reaching danger levels.

FXE's price was largely stable on both Friday and Monday, declining slightly. But the ETF rose 1.31 percent Tuesday, closing at 131.83.