Citigroup Flags Highest Stock Market Bubble Risk Since 2008, But Says Overheating Not Yet Reached

According to Citigroup's bear market checklist indicator, the level of froth in global equity markets has reached a post-2008 financial crisis peak, yet the overall market has not yet entered an overheated state.

A research team led by Beata Manthey at Citigroup wrote that, despite global stock indices nearing record highs, the bank's Bear Market Checklist (BMC) is not flashing signals of excessive market euphoria.

Consequently, the strategists maintain a bullish stance on equities. However, they note that if the indicator deteriorates further, they would no longer recommend buying on market dips.

This checklist encompasses 18 detailed metrics across areas such as valuations, market sentiment, credit spreads, and fund flows. Currently, global stock markets are triggering 10 of these warning signals, the highest number since the financial crisis, indicating a deepening of market froth.

Breaking it down by region, U.S. stocks show 11.5 warning signals out of a possible 18, highlighting signs of an overextended rally. Europe, in contrast, has triggered only 5 signals, indicating a relatively more stable market condition overall.

Even with the rising indicator readings, the global Bear Market Checklist has not yet reached the extreme warning levels seen prior to past bear markets. The indicator hit 17.5 before the 2000 dot-com bubble and reached 13 ahead of the 2008 financial crisis.

The research report notes that elevated valuations across multiple sectors, persistently optimistic investor sentiment, and a surge in IPO and equity financing activity—all reflecting high market risk appetite—are typical characteristics of the late stage of an economic cycle.

Significant capital expenditure growth driven by major AI cloud providers, along with a wave of IPO launches and preparations by U.S. mega-caps, has pushed several metrics into warning territory. Strong global corporate earnings per share (EPS) growth and continued net inflows into equity funds are also contributing to the rise in the indicator.

Some metrics still support the market rally: credit spreads remain low despite a gradual flattening of the yield curve this year. However, the report warns that if risks in private credit or debt issuance concerns stemming from AI-related capital spending materialize, market risks could escalate rapidly.

Citigroup maintains a bullish outlook on stocks for the full year but remains vigilant about rising risks. The strategists state that historical patterns show that once the number of triggered warning signals breaks into double digits, it often accelerates higher thereafter.

The team adds that if the indicator continues to worsen, the strategy of buying on market dips should be abandoned at that point.