Galaxy Macau, the newest resort in Macau, is lit up in the evening after it opened for business on May 15. Macau, the world's biggest gambling destination, is located on the southern tip of China, which puts it about an hour away from Hong Kong by ferry. REUTERS/Bobby Yip

Gambling revenues for August in Macau were the second best ever in the legendary casino city, according to a Citigroup Inc. (NYSE:C) research note.

Total Macau gross gambling revenue reached 30.7 billion Macau patacas ($3.84 billion) for August, up almost 18 percent from the year before, according to Citi analysts.

So far this year, gamblers spent 16 percent more than last year’s similar period, according to government data. The best month on record happened in March 2013, when gamblers spent 31.3 billion patacas.

The gambling market in Macau, a former Portugese colony just dozens of miles from Hong Kong and mainland China, is split into mass market gamblers, or ordinary casual gamblers, and so-called VIP gamblers, or high rollers.

Revenue from ordinary gamblers rose 44 percent from August 2012, to a record of 9.9 billion patacas, wrote Citi analysts, beating a 9 billion pataca record set in July.

Big spenders have trafficked Macau’s 30-plus casinos more and more since October 2012, wrote analysts, with each month since then posting growth in traffic over the year-ago period.

Major casino operators in Macau include Sands China Ltd. (HKG:1928), which Citi estimates as Macau’s largest by market share, and SJM Holdings Limited (HKG:0880).

According to Reuters, analysts are mostly optimistic about the growth of the gambling market in Macau, with low market penetration and strong consumer sentiment driving it, despite slowing Chinese economic expansion. Two-thirds of Macau’s visitors come from China.

The Macau market has long outstripped Las Vegas and even broader Nevada, according to gambling blog Card Player. Nevada typically earned under $1 billion in monthly revenue in 2013, compared to Macau’s consistent pace of more than $3 billion in monthly revenues.

Casinos paid 99.6 billion patacas in tax revenue in 2011 and paid their employees a total of 12.2 billion patacas, according to government data.

It’s unclear exactly why gambling revenue broke monthly records for August, though Citi analyst Anil Daswani previously noted that gamblers even braved the severe typhoon Utor in August.

September figures are more likely to be subdued, however, with lesser gains than August, he predicted.