let's bring in matt maley, from miller tabak and kelly jones with the schwab center for research. welcome, guests. matt, let me start with you. how do you distinguish between what is, as some are describing this, a constructive sell-off, a welcome pullback? you know thead ctives. and one that is less constructive and less welcome? f at are the telltales? >> onee most important things we look at is, if you see a deterioration in the underlying, not just in the economy, but the underlying of the keys, and o things is watching credit spreads, especially high-yield credit reads. now, they have widened out a little bit recently, but only slightly and they've g very, very tight. so, this is not the big kind of tdening out that would signal that we're going see a big decline like we saw in 2008 or in 2000 in the stock market. and i think as m aeuded to earlier in the day, is that we don't really get -- you markets very rarely crash from the top. they usually have a sell-off a a retest and internals are poor with poor advanced deines, lousy volume when you get that retest. that signals tha