Wall Street's most vocal bull, and author of a 10,000 price target for the S&P 500 by the end of the decade, is getting bearish.

Well, at least a little.

Ed Yardeni, founder and president of Yardeni Research and one of the most respected voices on Wall Street, ripped 500 points from his end-of-year S&P 500 price target on Wednesday. Emerging recession risks tied to the U.S. war with Iran, the surge in global crude prices, and the continued march higher in Treasury yields were factors behind his more cautious forecasts.

"We still anticipate that the economy will grow without a recession through the end of the decade," Yardeni said in a note published Wednesday. "But the risks of a downturn have increased over the next three to six months, as reflected in the higher odds we assign to a bearish scenario."

Yardeni now sees the S&P 500 finishing the year at 7,900 points, which suggests a modest 4.1% gain from current levels. His previous 2026 target of 8,400, once the highest on Wall Street, has been pushed out to mid-2027, while he continues to hold to his 10,000 point forecast for the benchmark by the end of the decade.

Yardeni, however, is still leaning into his "Roaring 2020s" scenario of continued economic growth, powerful equity market returns fueled by exceptional earnings growth and high profit margins, and a resilient U.S. consumer anchored by a strong labor market.

But he's starting to feel slightly less confident in that outlook as markets enter a difficult autumn season, colored by midterm elections that could change the tenor of government policy for the next two years and the tensions in the Gulf region and Eastern Europe.

"We've shaved the subjective odds that we ascribe to that scenario from 80% to 70% and now see a 30% chance that rising geopolitical and other risks could derail it," he said.

Multiple drivers could hinder the stock market's climb, but perhaps the most glaring is the Treasury market. Rising bond yields create an compelling investment alternative to stocks, while simultaneously lowering the present value of future company earnings, which is the most important component of an equity price.

Stocks have seen notably slower gains in recent months as U.S. government bond yields have powered relentlessly higher.

The yield on the 10-year note has risen more than 65 basis points since the end of June to 5.03% earlier this week, marking its highest level since 2007. Yields on longer-dated 30-year bonds, meanwhile, hit a fresh pre-financial crisis high of 5.37% on Tuesday, and have added around 50 basis points since the start of July. (A basis point is 0.01%)

The S&P 500, meanwhile, had been off to a roaring start in 2026, first topping the 7500 point mark on May 14, for a year-to-date gain of 9.6%. But it has stalled since then, gaining only 1.1% over the past 84 trading days-despite a storming second-quarter earnings season where collective profits rose 34.5%.

Those bond market moves have come amid a massive rise in global oil prices-tied to disruptions from the war with Iran-as well as U.S. debt and deficit tallies that have spooked investors in fixed-income markets all over the world.

There are also growing concerns that inflation risks are becoming more deeply embedded in the world's biggest economy as elevated energy prices have a domino effect on transportation, travel, materials, and many other sectors.

"The longer oil prices remain elevated, the greater the risk that inflation becomes entrenched, especially given the economy's resilience," Yardeni warned.

Jeffrey Gundlach, founder of DoubleLine Capital and one of the market's most formidable bond trading voices, warned on social media Tuesday that inflation "is not going down any time soon." He predicts that the next U.S. consumer price index reading could spike to the 4% range, which would be a sharp jump from August's 3.4% pace.

While the Federal Reserve is broadly expected to raise interest rates on Wednesday, Yardeni fears that the rate increase could be coming too late to rein in inflation effectively.

"We had previously argued that a Fed rate hike in July would have pushed the 10-year yield lower by bolstering the Fed's inflation-fighting credibility," Yardeni said. Wednesday's rate decision and the fresh set of growth, inflation, and unemployment forecasts from policymakers, however, could still lead to that outcome, he says.

But remember that the shift in Yardeni's stance is all relative-he is still a bull at heart.

Yardeni-who first coined the term "Bond Vigilantes" in the early 1980s, referring to the manner in which bond markets can lead government policy changes-isn't overly concerned with the move higher in Treasury yields, nor the impact it appears to be having on stock performance. But he is mindful of the fact that 10-year notes are edging beyond the 5% threshold.

"We've said it before, and will say it again: We will worry about a debt crisis when the bond market worries about a debt crisis," Yardeni explained. "We are starting to worry now that the 10-year U.S. Treasury bond yield may be on the verge of breaking out above 5%."

Trading north of 5%, Yardeni says, underscores the market's broader concerns tied to the war with Iran, oil prices, and the government's deteriorating finances, as well as Treasury Secretary Scott Bessent's attempts to bring down yields.

"Proceed with caution," he warned.

That isn't what we're used to hearing from the bulls, but it's worth heeding nonetheless.