Updates levels at midday

HONG KONG/SHANGHAI, Dec 3 (Reuters) - China's main stock indexes fell on Tuesday as chipmakers wobbled after the latest U.S. clampdown and financial firms dragged on the broader market on expectation falling interest rates will squeeze insurers' returns and lenders' margins.

The United States on Monday launched its third crackdown in three years on China's semiconductor industry, curbing exports to 140 companies to stymie China's ability to access and produce top-line chips.

"It was not a blanket ban, or as stringent as people first feared. So that, to me, is a positive," said Tai Hui, Asia chief market strategist at J.P. Morgan Asset Management in Hong Kong.

"That said, I think we've seen in the past few years, things get tighter and tighter."

Mainland indexes of global chipmakers .CSI931998 and chip-making materials firms .CSI931999 climbed around 2%, while designers .CSI932040 and even toolmaker Piotech 688072.SS, one of the companies newly targeted by the U.S., rose around 1%.

However, an index of domestic semiconductor firms .CSI931865 fell 2.6%, albeit barely denting the 50% gains that sub-index has had in three months.

By midday, the Shanghai Composite index .SSEC was down 0.27% at 3,354.95 points while the blue-chip CSI300 index .CSI300 was down 0.55%.

Chinese H-shares listed in Hong Kong on the Hang Seng China Enterprises Index .HSCE were flat, as was the Hang Seng Index .HSI was up 0.19% at 19,587.73.

In addition to having become more inured to U.S. crackdowns after years of restrictions, investors in China's semiconductor industry see targeted firms as likely to garner state support or, at least, earn revenue that would otherwise have flowed to global giants.

The broader market was weighed down by a gloomy economic outlook for China that has investors expecting further interest rate cuts, underlined by a weak reading for non-manufacturing spending.

Benchmark 10-year bond yields CN10YT=RR fell to their lowest on record on Monday as widespread lack of confidence in the property sector and a drifting stock market drives money into debt markets.

Financial stocks .CSIFN dropped early in the day but pared some losses to be down 0.07% at 0530 GMT. The yuan CNY=CFXS touched a one-year low of 7.2890 per dollar while ten-year Treasury futures CFTc1 hovered near record highs. CNY/

(Reporting by Jiaxing Li in Hong Kong and Reuters' Shanghai Newsroom; Writing by Tom Westbrook in Singapore and Edwina Gibbs; Editing by Lincoln Feast.)

((tom.westbrook@tr.com; +65 6973 8284;))