As Taiwan's stock market plunged more than 400 points, all four Formosa Plastics Group companies moved into positive territory — good news for investors looking to avoid the sell-off in tech stocks.

• Memory, passive components and silicon wafers were the hardest-hit sectors, leaving only shipping, financials and petrochemicals to hold up the market.

• Safe-haven funds flowed into the Formosa Plastics Group's "four treasures," with Formosa Petrochemical — down more than 7% the previous day — leading the gains, and Nan Ya Plastics also turning higher.

• Foreign investors were net sellers of NT$15.7 billion the previous day, dumping the four companies heavily, while retail investors moved in to bottom-fish.

• Institutional analysts expect the diesel crack spread to hold at US$70 a barrel, a record high for the same period, and have given Formosa Petrochemical a buy rating with a target price of NT$90.

Outlook: With European diesel stockpiling demand rising over the winter, supply and demand for refined products is tightening, and refining margins are expected to stay elevated.