Oil prices fell back suddenly over the last few trading sessions, dragged down by some forces beyond the oil market. 

The steady decline of the U.S. dollar has helped drive up crude prices for weeks, but that came to an abrupt halt last week. A rebound for the greenback led to a steep decline in oil prices on Friday. 

At the same time, sudden turmoil in the broader financial system also bled over into the oil market. Volatility in the stock market flared up on Friday, sparking the sharpest single-day upheaval in years. 

The Dow Jones Industrial Average fell more than 600 points, only the ninth time in history that a fall of that magnitude has occurred. “The stock market and interest rates can really affect oil a lot,” Mark Waggoner, president of Excel Futures, told The Wall Street Journal. “It’s spilling over into the energy markets and causing these ripple effects.” 

The stronger-than-expected job growth and wage increases fueled speculation that the Fed would tighten interest rates more than previously thought. Bond yields continue to rise, undercutting equities. Signs of higher inflation also led to speculation of interest rate hikes from the central bank. The dollar gained 0.7 percent on Friday. 

That led to a sell-off for Brent and WTI. And if the turmoil continues, the trouble for oil benchmarks will also linger. “The potential is present for a big move lower should fear return to the stock market and spark liquidations across the board,” analysts at TAC Energy said Friday, according to The Wall Street Journal. “The cross-asset-class correlations have returned over the past several weeks.” 

The problem for oil is that both oil prices and broader stock indices are seen as overvalued by some analysts. Hedge funds and other money managers have piled into bullish bets on crude, leaving positioning in the futures market overextended.