The Direxion Daily FTSE China Bull 3X Shares ETF (YINN) soared over 14% on Monday, riding a wave of optimism surrounding potential new stimulus measures from China's government to revive the country's slowing economic growth.

YINN, a leveraged ETF that seeks to deliver three times the daily returns of the FTSE China 50 Index, surged ahead of a highly anticipated press briefing by China's top economic planner, the National Development and Reform Commission (NDRC). The briefing, scheduled for Tuesday, will discuss a package of policies aimed at boosting growth, according to a government notice on Sunday.

Investor sentiment towards Chinese stocks and related ETFs has turned increasingly bullish in recent days, as Wall Street firms like Goldman Sachs, HSBC, and BlackRock have grown more optimistic about the potential impact of Beijing's stimulus blitz. Goldman Sachs upgraded its rating on Chinese equities to "overweight" on Thursday, projecting further gains of 15-20% if authorities deliver on the promised measures, which are expected to include interest rate cuts, increased bank lending, and direct support for the stock market.