Stocks have recovered from their declines earlier this year, but are in need of an upward catalyst, according to one expert.

"We saw stocks reach their year-start levels, so that was a positive point," said Simon Smith, chief economist at FxPro, based in London. "If we're going to move into positive territory for the year on the S&P 500 (SPY) - Get Report , we need a reason for that. And I think that's what the market is struggling for at the moment."

After a few stints with slight year-to-date gains for the S&P 500, the broad index fell back into the red on Thursday, falling 0.8% year to date. Thursday is the final trading session of the week, as the markets are closed on Friday for the Good Friday holiday. Stocks are on track to disrupt their prior momentum of five straight weeks of gains.

The declines on Thursday stemmed from oil prices slipping back below $40 a barrel as supply concerns continue to plague the global oil market.

"We were in the $20s, which is what you would describe as oversold levels," he said of oil prices. "I think the move we've seen, touching $40 a barrel, is warranted."

Smith said the market will now be focused on possible production freezes and whether or not that will include OPEC nations. If OPEC froze production, that would provide some stability for oil prices.

"I think we're going to [have to be content] with being comfortable with oil near the $40 handle for the time being," he said.

Prices for West Texas Intermediate crude oil, the U.S. benchmark for oil, slumped 3.6% since the start of the year and 32% over the last 12 months.

Meanwhile, the dollar gained steam this week against other currencies, buoyed by last week's dovish remarks from theFederal Reserve, Smith said. The tragic attack in Brussels earlier this week also pushed the dollar higher amid renewed uncertainty in global conditions.