China (FXI). 

A closing break below 37.17 (Feb. 8 low) indicates a move to 30 - 32, which is a 30% decline from its April 9 closing of 44.59.

Last decline was Nov. 16 to Feb. 8, which was 20% down. 

S&P 500 (SPX) declined 8% during its previous drop (Jan. 19 to Feb. 8).

If China goes down 30% this time and the price relationship holds, then SPX drops 15% to 1034.

Key levels for SPX: 1110 (closing low of May 7), then 1056 (Feb. 8 closing low).

A market correction (15% to 1034) with a breach of the SPX Feb. 8 low (1056) should raise bearish sentiment and produce an oversold condition to sufficient levels to trigger a summer rally. It will likely fail as many global markets would have triggered a Mega Trend reversal (price to moving averages (50 and 200 day), and slope of moving averages): just as the accompanying chart shows China doing right now (as is EAFE (EFA), Europe 350 (IEV), Germany (EWG), and United Kingdom (EWU), among others.*

If all occurs: Bull market over.