Investors should be wary as the recent spike in market volatility is quite rare, according to the manager of the California State Teachers’ Retirement System, which contains more than $200 billion in assets.

“The last few days have been abnormal volatility,” Christopher Ailman, chief investment officer at CalSTRS, told CNBC Thursday night during a special aired. “The volatility we saw earlier in October and November, I went on and said that was expected. That’s typical when you have a bull market that’s so old and so late in the economic cycle. But the last few days are abnormal because the machines are really picking over more than human beings.”

Ailman’s comments follow after yet another fierce day on Wall Street. The Dow Jones Industrial Average close 260 points higher on Thursday, eliminating a 611-point decline from earlier in the day. Thursday’s rally followed a historic day in the U.S. stock market on Wednesday, in which the bluechip index posted its biggest one-day points gain in history.

Just days after Wall Street logged its worst Christmas Eve performance ever on Monday, stocks suddenly began increasing. “That’s normally a quiet day and that was crazy to see that decline,” Ailman said.

Investors have been quite worried lately due to a possible monetary policy mistake from the Federal Reserve, an ongoing U.S. government shutdown, U.S.-China trade talks and a possible economic slowdown. According to Ailman, investors should look at the bond market for clues regarding the economy rather than stocks itself.

“Bond yields have held in there,” he said. “The stock-market volatility is just too extreme in this environment.” Though, he also noted the economy is still “stable.”