It has been one of the best kept secrets in the tech world, but in a letter to shareholders, Amazon CEO Jeff Bezos has revealed its Prime offering now has more than 100 million subscribers worldwide.

Bezos has always been cagey regarding the service, which launched 13 years ago, with this being the first time a number has been assigned. Analysts estimated the service had collected more than 90 million subscribers last year, though it will come as a surprise to very few that this number has been superseded.

“13 years post-launch, we have exceeded 100 million paid Prime members globally,” said Bezos in the letter. “In 2017 Amazon shipped more than five billion items with Prime worldwide, and more new members joined Prime than in any previous year – both worldwide and in the US Members in the US now receive unlimited free two-day shipping on over 100 million different items.

“We expanded Prime to Mexico, Singapore, the Netherlands, and Luxembourg, and introduced Business Prime Shipping in the U.S. and Germany. We keep making Prime shipping faster as well, with Prime Free Same-Day and Prime Free One-Day delivery now in more than 8,000 cities and towns. Prime Now is available in more than 50 cities worldwide across nine countries. Prime Day 2017 was our biggest global shopping event ever (until surpassed by Cyber Monday), with more new Prime members joining Prime than any other day in our history.”

The letter seems to be a reminder to shareholders about the Amazon business model on the whole, and the riches which can be collected through large investments betting on the long-term business. The timing of this exercise of back-patting is quite curious, as Amazon will be reporting the financials for Q1 in exactly one week. This of course might be a coincidence, but very few things in the world of multi-billion dollar business are.

Perhaps Amazon is about to unveil a poor financial performance or at least one which is below analyst expectations, or might Bezos be planning another monumental capital expenditure to diversify the business further. Reminding shareholders of the value of long-term thinking would fit into both categories, but we suspect the latter might be true.

Prime certainly has been a long-term strategy, taking 13 years to get to 100 million customers, slow by Amazon standards. However, Bezos has consistently pumped cash into the venture, continuing to expand the value proposition to customers. From ‘free’, speedy delivery of Amazon purchases, to TV, music, fashion, a virtual library, free delivery on ‘Fresh’ orders and cashback on a Prime Visa Signature Card. It has also been unveiled the Whole Foods will also be folded into the subscription. Creating this much value for subscribers cannot have been cheap for Amazon, but with 100 million customers the profits are now there to be made.

This is the Amazon way, it is very long-term thinking with a fail-fast mentality. It is not cheap, but then again the profits on the horizon promise to be vast. Perhaps this was the purpose of this letter; remind shareholders of what can be achieved if you buy into the Amazon business model, before announcing something which might make a few uncomfortable.