BEIJING (Reuters) - China and the United States made "significant progress" in talks last week on investment rules, state news agency Xinhua reported on Sunday.

Reaching an agreement over the so-called 'negative list' of businesses in China that are out of bounds to foreign investors is crucial in sealing a treaty between Beijing and Washington that would lift investment flows between the world’s two largest economies.

The issue has been made more prominent by a wave of Chinese acquisitions of U.S. companies that have raised questions over the inability of U.S. companies to buy assets as freely in China.

During last week's meeting in Beijing, the two nations exchanged for the third time the latest revised draft of the negative list.

"This signals a common goal to establish an investment system that is non discriminative, transparent and open," a Ministry of Commerce spokesman was quoted as saying on Sunday.

"Two sides will intensively push for further negotiations, expedite the work pace in order to reach a win-win, high level investment treaty."

China has not made public the negative list, although sources told Reuters previously that the number of items on the list in earlier drafts had fallen to between 35 and 40, from around 80 previously.

Securing an investment treaty with the United States could bring a much-needed boost to China’s slowing economy, where domestic investment is at its lowest since 2000.

(Refiles to change day of comment in paragraph 5 to Sunday)

(Reporting by Chen Aizhu; Editing by Kim Coghill)