Stocks soared after President Donald Trump’s election, but economists are afraid that success will be short-lived.

Many investors turned bullish after Trump won the election, largely due to expectations he would quickly usher in a slew of business-friendly policies while cutting regulations. But now that he has been in the Oval Office for nearly 100 days and has yet to implement serious reform, the market is sending worrisome signals, the Wall Street Journal reports.

Experts said a quick drop in government-bond yields is the most obvious sign, with the 10-year U.S. Treasury yield recently hitting a five-month low. At the same time raw materials markets are weakening as copper and iron ore prices fall.

Economists said these signals could be due to economic weakness, which would result in falling stocks and geopolitical worries — all of which is bad news for the commercial real estate industry. Experts recommend investors watch the market carefully and remember that slow growth and climbing rates are a dangerous combination.