Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

All the king's horses and all the king's men, as well as a slew of economic data, couldn't bring the S&P 500 (SNPINDEX:^GSPC) back into positive territory again – at least for today, that is!

The ongoing threat of a protracted government shutdown looms large, and the U.S. is expected to hit its debt limit in about two more weeks. Even the Treasury Department warned that things could go from bad to worse if the U.S. defaults on its October interest payment. As much as investors would like to blow this off as they did earlier in the week, a third straight day of political gridlock is bringing into full view the reality of the possible negative consequences of the shutdown.

On the economic data front, initial jobless claims nudged higher by a seasonally adjusted 1,000, to 308,000. Although this is a figure we'd prefer never rise, a relatively steady initial claims figure would continue to point toward an improving jobs market.

Conversely, the Institute for Supply Management non-manufacturing index fell to 54.4 in September from a reading of 58.6 in August, far lower than economists had expected. Weaker growth here could be a signal that consumer demand isn't picking up as expected, which could negatively impact U.S. GDP.

All told, the S&P 500 dipped by 15.21 points (-0.90%) to finish the day at 1,678.66, its ninth drop in the past 11 sessions.

Aggressively moving higher yet again was hospital operator Tenet Healthcare (NYSE:THC) which jumped 5.4% after earlier this week completing its $1.8 billion purchase of Vanguard Health. Today's move appears to be a continuation of yesterday's praise from Fitch, which called the combination "strategically sound." However, while I do expect hospital operators to benefit from the Obamacare overhaul that should see more people signing up for health insurance, Tenet is overly exposed to the 22 states that are not, or have considered not, expanding their Medicaid programs. Given that fact, Tenet's doubtful revenue collections are likely to fall by less than its peers, putting it in a disadvantageous scenario.

Apparel and accessories company PVH (NYSE:PVH) added 4.4% after announcing the sale of G.H. Bass. to G-III Apparel Group (NASDAQ:GIII) for $50 million. With PVH commenting that it's focused on building core lifestyle brands Tommy Hilfiger and Calvin Klein, its G.H. Boss outlet stores became expendable. Because of the sale, PVH also slightly raised its third-quarter earnings-per-share forecast to $2.25 from $2.20. For G-III, the G.H. Boss outlets will help expand the company's product offerings both vertically and geographically. Although a short-term curb on EPS, the deal is expected to be earnings accretive in 2014 and beyond.

Finally, spirits maker Constellation Brands (NYSE:STZ) popped 3.2% after its second-quarter earnings topped Wall Street's expectations. For the quarter, revenue exploded higher to $1.46 billion from $698.5 million in the year-ago period, thanks predominantly to Constellation's acquisition of Modelo Group's assets in the United States. On an adjusted EPS basis the company earned $0.96 compared to just $0.71 a year earlier and the $0.88 per share forecast from Wall Street. As icing on the cake, Constellation also raised its full-year EPS guidance to $2.80-$3.10 from $2.60-$2.90. The diversity that Modelo Group's U.S. assets offer Constellation is beginning to pay dividends and I wouldn't discount the idea of Constellation possibly even heading higher.

Fool contributor Sean Williams has no material interest in any companies mentioned in this article. You can follow him on CAPS under the screen name TMFUltraLong, track every pick he makes under the screen name TrackUltraLong, and check him out on Twitter, where he goes by the handle @TMFUltraLong.

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