Norway, Western Europe’s largest producer of oil, has decided it doesn’t want to be so beholden to the fortunes of the oil industry anymore. Norway’s central bank recommended today that the nation’s giant sovereign wealth fund should dump its holdings of oil and gas stocks, which make up about 6% of the fund’s benchmark equity index, worth a whopping $37 billion in assets.

For almost three decades, Norway has been putting surplus revenues from its oil and gas production into a sovereign wealth fund. Now, the fund has more than $1 trillion in assets, making it the largest sovereign fund in the world; it owns 1.3% of all global stocks.

In a letter to the Norwegian ministry of finance, the central bank recommended the removal of oil stocks to make the fund—and the government’s wealth— less vulnerable to a permanent drop in the oil price. It says the fund’s existing holdings and the government’s stake in Statoil mean the country already has an outsized exposure to the oil and gas industry. (Last year, the fund sold shares in 52 coal-dependent companies, on environmental grounds.)

The finance ministry said it would decide on the plan next year. Parliament would need to approve it for the move to go into effect. The possibility of the fund selling $37 billion in stocks was enough to send Europe’s oil and gas companies into the red, putting an abrupt end to what had been a positive day of trading before the announcement.

Recently, Norway’s fund has benefitted from an increase in oil prices. In the third quarter of 2017, oil and gas stocks were the best performing asset class for the fund, delivering an 8.7% return. Shell was the fund’s best-performing stock for the quarter, of which the fund owns more that $5 billion in shares.

At the end of 2016, the fund had holdings in 379 oil and gas stocks. Here are the five largest: