A measure of implied volatility on Wall Street Monday rose by the most since February as the Dow Jones Industrial Average /zigman2/quotes/210598065/realtime DJIA +0.68% tumbled nearly 1,000 points at its lows on concerns about China's property market highlighted by the potential collapse of China Evergrande Group. The CBOE Volatility Index /zigman2/quotes/210598281/delayed VIX -19.78% jumped by about 32% to 28.30, marking its biggest one-day rise since Feb. 25, when it rose 35.4%, FactSet data show. The index, also known as the VIX, for its ticker symbol, has become well known as Wall Street's "fear gauge," since it was created in the early 1990s. The VIX itself, which uses S&P 500 options to measure trader expectations for volatility over the coming 30-day period, tends to rise as stocks fall and is often therefore referred to as a guide to the level of investor fear. The S&P 500 index /zigman2/quotes/210599714/realtime SPX +1.32% was trading 2% lower at 4,343, which would mark its steepest drop since May 12, according to FactSet data. The Nasdaq Composite Index /zigman2/quotes/210598365/realtime COMP +1.88% was down 2.6% to 14,653, which would also represent its sharpest daily lose on a percentage basis since May 12. The Dow /zigman2/quotes/210598065/realtime DJIA +0.68% was trading 1.9% lower at 33,921. but had been down by as many as 970 points. The decline for stocks also came as the benchmark 10-year Treasury note yield /zigman2/quotes/211347051/realtime BX:TMUBMUSD10Y -1.99% fell by the most since Aug. 13, down 6.1 basis points to 1.308%, Dow Jones Market Data show. Evergrande, a Chinese property giant nursing more than $300 billion in debt, remains on the brink of default - sending global equities tumbling Monday as investors, who had previously ignored the situation, sat up and took notice.