* HSI -1.2 pct, H-shares -1.0 pct, CSI300 -0.2 pct
* Hong Kong's fall erases index gains late Tuesday
* China earnings a mix of winners and losers
By Natalie Thomas
BEIJING, April 30 (Reuters) - Hong Kong stocks fell on Wednesday, as profit-taking by investors erased the gains many stocks made during a surge late in the previous day.
China stocks were flat as there was a mix of winners and losers from a flood of first quarter results ahead of the two-day national holiday starting Thursday.
At midday, the Hang Seng Index was down 1.2 percent at 22,195.89 points. In the last hour on Tuesday, the index gained 1 percent.
The China Enterprises Index of the top Chinese listings in Hong Kong dropped 1.0 percent.
The CSI300 index of the largest Shanghai and Shenzhen A-share listings was down 0.2 percent, while the Shanghai Composite Index was flat at 2021.02 points.
On the mainland, investors favoured healthcare stocks, lifting the CSI300 healthcare subindex 0.9 percent.
Gains were led by Yunnan Baiyao Group Co Ltd, which jumped 3.3 percent after posting a 34 percent year on year increase in Q1 profits on Tuesday.
Other pharma firms continued to rise after releasing earnings on Monday. Jiangsu Hengrui Medicine Co Ltd shares were up 2.6 percent and Guangzhou Baiyunshan Pharmaceutical Holdings Co Ltd gained 1.9 percent.
But shares in Industrial and Commercial Bank of China Ltd (ICBC) declined 0.6 percent even as the bank beat estimates with a near 7 percent rise in first-quarter net profit.
The "Big Four" banks have all posted expectation-beating first quarter results, ( ) but investor reaction has been muted, as concerns remain about exposure to bad loans and competition from online wealth management products.
In Hong Kong, losses were exacerbated by a decline in index heavyweight Tencent, which shed 3.0 percent as investors worried about censorship in its online video platforms and a depreciation in the yuan.
"This trend will discourage investors from buying stocks which have huge amounts of assets in RMB, as the depreciation will hurt their overall valuation," said Castor Pang, head of research at Core Pacific-Yamaichi in Hong Kong.
Shares in China's top aluminium producer Aluminium Corp of China Ltd (Chalco) dropped 3.1 percent in Hong Kong and 1.6 percent on the mainland after the firm posted a $345 million loss for the first three months of 2014.
Esprit Holdings shares fell 4.1 percent after the company reported a 9.9 percent decline in third-quarter turnover.
The decline came as the company is restructuring effort aimed at shortening production times, shuttering unprofitable stores and boosting profitability.
The Shanghai and Shenzhen stock exchanges will close for the next two days for holidays, and reopen on Monday. (Additional reporting by Donny Kwok in Hong Kong; Editing by Richard Borsuk)