SHANGHAI, Nov 3 (Reuters) - China's mutual fund companies are rushing to buy their own stock products - a signal that could stabilise sliding markets amid strong outflows and a sluggish turn in the economy.

"We firmly believe that China's economy will improve in the long term," wrote Li Yimei, chief executive officer of China Asset Management, one of several major firms that each vowed to allocate 200 million yuan ($27.3 million) to fund purchases this week.

China's stock market has reached a bottom and it is good buying time for contrarian investors, she said.

Southern Asset Management, Fullgoal Fund and GF Fund Management have also pledged to invest 200 million yuan in their own equity fund products, citing long-term confidence in China's capital markets.

The moves come after state fund Central Huijin bought stocks to stem declines in the equities market that last month hit its weakest since 2019 as sustained foreign selling took a toll.

Chinese funds also elevated share purchases during the 2015 stock market crash, under regulators' guidance, which helped spur some rallies though that did not reverse market losses.

"A prevailing risk-off sentiment had a significant impact on fund flows," said fund consultancy Z-Ben Advisors. China's active equity funds booked $18 billion in outflows during the July-Sept period, the biggest quarterly loss this year, its data shows.

The promises by fund managers to increase investment in stocks also followed encouragement by some authorities to invest. China's social security fund urged investors to strengthen their counter-cyclical investment mindset last week.

Since late August, 35 fund houses have vowed to step up fund purchases totaling 2.6 billion yuan, state-backed newspaper China Fund said on Thursday.

So far this year, more than 140 fund companies have purchased their own products, with the investment in equity funds near 4 billion yuan, the newspaper added.

Moreover, more Chinese listed companies also unveiled share buyback and purchase plans. The benchmark CSI300 index rose 0.8% on Friday, in line with global gains as investors bet on an end to interest rate hikes in the United States. ($1 = 7.3164 Chinese yuan) (Reporting by Jason Xue in Shanghai and Tom Westbrook in Singapore; Editing by Jacqueline Wong)