There’s one more sign that Amazon.com Inc. is close to choosing a site for its sprawling second headquarters from among Denver and 19 other locations.

NBC News reports that the e-commerce titan has finished its site tours of all 20 finalist cities.

It cites unnamed “sources close to the process” in its report.

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Says NBC:

This pushes the Seattle-based company one step further in deciding which city will become “HQ2,” a move that would net a $5 billion investment and as many as 50,000 high-paying jobs, according to Amazon.

In early April, a CNBC report said Amazon executives had “visited more than 10 of the final 20 cities” – suggesting that as recently as a few weeks ago, there were several more to visit.

What happens on Amazon’s site visits? A Wall Street Journal piece in April had this to say:

People familiar with the visits describe whirlwind trips with Amazon’s small economic-development team. Led by Holly Sullivan (the executive leading the search), it examines data provided by the cities – such as the ACT and SAT scores of local high-school students – and asks probing questions regarding how much talent Amazon can attract.

> RELATED: How bad does Denver want Amazon HQ2? Not so bad, survey says

Amazon executives reportedly scouted the Denver area in February, dining in secret with Gov. John Hickenlooper at the time.

All Amazon has said directly so far is that it plans to announced the HQ2 city later this year.

The current finalist list of 20 finalists was winnowed down from nearly 240 cities that submitted bids.