This week's official purchasing managers' index (PMI) for China missed some important components without any explanations, leaving strategists slightly puzzled as they try to assess what's going on in the world's second biggest economy.
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The data on activity in the manufacturing sector for June was released on Monday without a breakdown of results for at least four of the 12 sub components. They were new orders, backlogs of orders, quantity of purchases made by firms and imports.
"I don't think there's anything nefarious about this, but I don't know why they didn't have all the data, it was a bit odd," said Alistair Chan, a China economist with Moody's Analytics in Sydney. "Hopefully we will get those other details of the PMI report at some point."
PMI numbers were released across the world on Monday and are usually looked at closely for the latest update on manufacturing activity.
In China, economic data have proved particularly market-moving not just because of the size of the economy, but also as investors try to assess the extent of a slowdown that could have ramifications elsewhere.
However, there has been some caution about Chinese economic data lately and economists warned in May that key trade numbers were probably being inflated by speculative capital inflows.
"Markets do have question marks about China data, especially after officials suggested the trade numbers were inflated earlier this year," said Dariusz Kowalczyk, senior economist and strategist at Credit Agricole in Hong Kong.
"The reporting of data in China is not as comprehensive as it is in other more developed economies, but on the other hand there are some areas of reporting such as on currency flows and currency transactions by corporates that is important and you don't get in other major economies [but China reports it] - this is worth highlighting," he said.
Filling in the Gaps
Analysts said that in terms of the PMI data for China, they looked to data from other providers to fill in the gaps.
"We do have the HSBC numbers so we can extrapolate from that," said Chan at Moody's Analytics, referring to a separate PMI survey published by HSBC.
Credit Agricole's Kowalczyk said he looked at information from global data provider CEIC for the missing sub components of the China PMI data.
- By CNBC's Dhara Ranasinghe; Follow her on Twitter: @DharaCNBC