a measure of implied volatility on wall street monday rose by the most since february as the dow jones industrial average djia tumbled nearly 1000 points at its lows on concerns about chinas property market highlighted by the potential collapse of china evergrande group the cboe volatility index vix jumped by about 32 to 2830 marking its biggest oneday rise since feb 25 when it rose 354 factset data show the index also known as the vix for its ticker symbol has become well known as wall streets fear gauge since it was created in the early 1990s the vix itself which uses sp 500 options to measure trader expectations for volatility over the coming 30day period tends to rise as stocks fall and is often therefore referred to as a guide to the level of investor fear the sp 500 index spx was trading 2 lower at 4343 which would mark its steepest drop since may 12 according to factset data the nasdaq composite index comp was down 26 to 14653 which would also represent its sharpest daily lose on a percentage basis since may 12 the dow djia was trading 19 lower at 33921 but had been down by as many as 970 points the decline for stocks also came as the benchmark 10year treasury note yield tmubmusd10y fell by the most since aug 13 down 61 basis points to 1308 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