Blame Macau.

Wynn Resorts (WYNN -1.78%) stock saw a 10.3% drop in November and Las Vegas Sands (LVS -0.37%) shares fell by 11%, according to S&P Capital IQ data.

The territory, which depends largely on wealthy Chinese gamblers, has been in a veritable free-fall for the past 18 months, which has dragged down stock prices for casinos dependent upon the region.

Source: YCharts.com

What: Both Wynn and Las Vegas Sands have bet heavily on Macao, which is a territory affiliated with China that's not exactly part of the country.

Wynn only owns two properties -- one in Las Vegas and 72% of another in Macao. The Sands has four hotel/casinos in Macao, three in Vegas and one each in Pennsylvania and Singapore. Because both companies have bet so heavily on the Chinese market they have been hurt by the Chinese government restricting high rollers from illegally bringing money from the mainland, Bloomberg reported.

So what: Macao has been struggling for a long time with casino revenue dropping for the 18th straight month in November, according to Bloomberg. Gross gaming revenue was down just over 32% for the month, according to data released by Macau's Gaming Inspection and Coordination Bureau, which is actually a slight improvement over the 35% yearly decline.

This "shows that the ongoing pressure on the high roller business hasn't been offset by mass market stabilization," said Bloomberg Intelligence analyst Tim Craighead.

Now what: It's a long slog for both casino operators. Things are not likely to improve in Macau anytime soon and the casino business in the United States is facing its own problems. Both companies could either be hurt or helped by the explosion of states allowing casinos in the U.S.

That could continue to harm business in Las Vegas, which would hurt Sands and Wynn. Either company could, in theory, also benefit from legalization by opening in a new market, but any significant changes are not going to be a quick fix.

Macau's fortunes are tied to the Chinese economy -- specifically its upper class. There's nothing to suggest a quick turnaround for China or for its wealthiest citizens. That leaves both casino operators with bleak short-term propositions and very uncertain long-term revenue pictures.