A closely watched measure of the Treasury yield curve temporarily inverted Friday for the first time since 2007, highlighting fears that a global slowdown will take a toll on the U.S. economy.

The yield on the 10-year Treasury note TMUBMUSD10Y, 0.675% fell nearly 8 basis points to 2.459%, a fresh 15-month low, briefly dipping below the three-month T-bill at 2.459%. An inversion of that portion of the yield curve is seen as a reliable warning of a potential recession within a year or two. Inversions have preceded every U.S. recession going back to 1955 with only one false positive, researchers at the San Francisco Federal Reserve found. While inversions of other portions of the curve have also served as recession indicators, the researchers said the 3-month/10-year measure is the most reliable.

Yields fall as bond prices rise.

Read:The yield curve inverted — here are 5 things investors need to know

“We can’t ignore rising recession risk, but for now it’s largely a story of global growth concerns, but if the global economy catches a cold, the U.S. won’t be immune,” said Tom Garretson, a fixed-income strategist at RBC Wealth Management, in a Friday note.

Bond yields around the world tumbled after a raft of disappointing purchasing-managers-index readings for the eurozone affirmed fears of lackluster growth in the 19-member group already contending with a trade slowdown and Brexit uncertainty. This comes after the Federal Reserve cut back on its interest-rate projections from two to none this week, with Fed Chairman Jerome Powell citing global economic headwinds for the cautious stance. Yields tend to retreat when growth prospects sour, and inflation fears have waned.

U.S. stocks, meanwhile, accelerated losses as the yield curve inverted.

See:S&P 500 could fall 40% as yield curve inverts, says analyst

Global bond-markets rallied on Friday, sending yields lower, as a raft of weaker-than-expected eurozone data drew investors into the perceived safety of government paper.

The 2-year note yield TMUBMUSD02Y, 0.144% tumbled 7.9 basis points to 2.332%, an around 10-month low, extending its weekly drop to 11.4 basis points. The 30-year bond yield TMUBMUSD30Y, 1.422% pulled back 6.9 basis points to 2.893%, its lowest since last January, contributing to a weekly decline of 12.7 basis points.

The yield for the 10-year German government bond TMBMKDE-10Y, -0.501% , or bund, fell 6.3 basis points to negative 0.02%, its lowest in nearly 2 1/2 years. Bunds are viewed as a proxy for the overall eurozone bond market.

See:Amount of global debt yielding less than 0% approaching $10 trillion

“The combination of a dovish Fed, slowing European economies and concerns over Brexit are contributing to lower yields globally,” wrote Tom di Galoma, managing director for Treasurys trading at Seaport Global Securities.

IHS Markit said its composite purchasing managers index for the eurozone fell to 51.3 in March from 51.9 in February, versus expectations for a decline to 51.8. A reading above 50 indicates growth in activity. The composite PMI for Germany, the eurozone’s largest economy, fell to 51.5 in March from 52.8 the previous month, a 69-month low.

The U.S. offered its own share of disappointing economic data. The Markit composite PMI fell to 54.3 in March from 54.3 in February, with the manufacturing component falling to 52.5, a 21-month low. Existing home sales rose to 5.51 million in February, after jumping from 4.94 million.

See: Europe manufacturing PMI signals deeper slowdown