China GDP: The elephant in the market

China's economic growth data for 2015 are due on Tuesday and markets are bracing for the slowest pace of expansion since 1990.

Growth for the fourth quarter is also expected to ease. This is what analysts are saying ahead of the release.

Nomura:

Nomura is forecasting fourth quarter GDP growth slowed to 6.4 percent on-year from 6.9 percent in the third quarter.

"The moderation would largely reflect a much smaller contribution from financial services (reflecting the slump in the equity market). However, growth in the rest of the economy should be similar to the third quarter, as weakness in mining, construction and heavy industry are largely countered by stronger public infrastructure spending, consumption and services," Nomura said in a note Friday.

"Overall, the timelier monthly data are likely to signal that growth is stabilizing (albeit at a low level and likely only temporarily), underpinned by the cumulative policy easing measures and consistent with the stronger-than- expected trade and total social financing data for December."

Mizuho Bank:

"Tell-tale signs of the slowdown from lethargic industrial activity to dismal PMI manufacturing have markets bracing for a disappointing read of between 6.9 percent. And the number may not be too far off, with possibility of 6.8 percent as the 'disappointment.' Nonetheless, 'hard evidence' of 2015 growth missing the 7 percent target (likely to be 6.9 percent) and slowing from 7.3 percent in 2014 is likely to renew pessimism," the bank said in a note Monday. "Bears will bemoan China's inability to rekindle growth despite the slew of stimulus launched via the monetary, banking and fiscal channels. And currency market cynics will seize this apparent policy impotency as grounds for yuan devaluation; a favorite conspiracy theory. And talk of 'currency wars' could potentially add to the bearish momentum in the markets."

Societe Generale:

"We expect a mild improvement in growth momentum, reflecting numerous monetary and fiscal stimulus measures," the bank said in a note Monday. "GDP growth is likely to have slowed another 0.1 percentage-point to 6.8 percent, mainly because of a much-reduced contribution from the financial sector."

Moody's Analytics:

"China's economy decelerated further in the final quarter of 2015, judging from slower growth in industrial production and fixed asset investment and falling exports and imports. Price pressures are nonexistent and the government cut interest rates in the quarter, which indicates a continued output gap and need for stimulus. Our tracking model puts GDP growth at 5.7 percent year-on-year, but the official series is expected to come in closer to 6.8 percent, possibly boosted by higher financial sector activity."

—By CNBC.Com's Leslie Shaffer; Follow her on Twitter @LeslieShaffer1