There are so many bulls in the US stock market that any disappointment on the economy or earnings poses a risk to the rally, according to Citigroup Inc. strategists.

Investor exposure to the S&P 500 remains extended and one-sided, even after bullish momentum has waned in recent weeks, a team including Chris Montagu said. About $10.7 billion of long positions on futures closed out last week, leaving net long positions at over $70 billion, the strategists noted.

“Overall positioning risk remains elevated and of concern, with notional levels still near long-term highs, if the current economic and earnings outlook were to abruptly surprise to the downside,” they wrote in a note.

US equities have surged about 19% this year, fueled by the buzz around artificial intelligence and bets the Federal Reserve will pivot its monetary policy before the economy faces a significant slowdown. Investors are bracing this week for comments from Chair Jerome Powell after the Fed’s rate decision on Wednesday, as well as a flood of corporate earnings.

Analysts slashed estimates in the run-up to the earnings season, setting a lower bar for companies. While the S&P 500 has risen about 1% since reporting kicked off in earnest on July 14, investors have punished firms that disappointed, such as Netflix Inc., which fell the most this year after its guidance missed estimates.

This article was provided by Bloomberg News.