The economy is flashing a worrying signal that hasn't been seen since right before the 2008 crisis

• The US economy is flashing a worrying signal about the health of the consumer.
• The gap between growth of GDP and gross domestic income hasn't been this large since 2007, Macquarie said.
• "All this doesn't augur well for consumer spending going forward."

The US economy could be in worse shape than previously thought. That's evidenced by a worrying indicator, which hasn't flashed a warning this loud since right before the 2008 recession, according to Macquarie strategists.

The asset manager pointed to the US's monster GDP growth over the third quarter, with the economy expanding at a revised clip of 5.2%. 

That's led some commentators to assume the economy is nowhere near a slowdown, but a closer look at gross domestic income — the measure of total compensation given to production — spells a different story.

Yearly growth in gross domestic product is currently outpacing gross domestic income by the most since 2007, Macquarie said in a note.

In theory, GDI and GDP should be equal to one another, but they can differ due to different methodologies. GDP measures the total value of production in the economy, while GDI measures the total compensation paid towards production.

The gap between the two could also explain why Americans feel poorly about the economy despite robust GDP growth, Macquarie added.

It could also explain why the labor market is beginning to slow: The unemployment rate remains near historic lows, but has climbed by 0.5 percentage points since April.

That all suggests there's "below-trend growth in real incomes, if not a recession," strategists warned, especially when considering the drawdown in household savings.

"All this doesn't augur well for consumer spending going forward," the note added. 

The firm has warned of a coming consumer-led slowdown, where sluggish consumers weigh down economic growth and push US economy to the brink of recession. That slowdown could come sometime before the first quarter of next year, Macquarie strategist Thierry Wizman previously told Business Insider.

Markets have been worried about a potential recession for the last year, but have started dialing back their recession bets as inflation continues to cool and prospects for a less hawkish Fed have grown.