Starbuck's is a central banker

MarketWatch: Some people keep their money in banks. Some keep cash beneath a mattress. Now there’s another place that people are depositing their money: their Starbucks accounts.

The Wall Street Journal recently reviewed data from S&P Global Market Intelligenceto determine where people are stashing their money these days, including banks, entities like PayPal Holdings Inc. PYPL, -0.97%  and other nonbanks.

Starbucks Corp. SBUX, -1.29%  , for one, had $1.2 billion loaded onto Starbucks cards and the Starbucks mobile app as of the first quarter of 2016, according to the data. This money can be used to purchase items including drinks, food and other merchandise.

Customers and clerks simultaneously bet on future coffee purchases; hence inventory flow of cups of coffee has controlled volatility, then  Starbuck's manager can set the risk bounds.  But the Starbuck's coin has to be traded against the tax dollar, somewhere.