The founder and CEO of the retail giant addressed a number of issues amid the usual chest beating these sorts of letters often contain. And he sent some warnings, both subtle and direct, to investors, letting them know that some bumps could lie ahead.

Here’s a look at four of the principle themes Bezos covered in this year’s note.

Antitrust scrutiny is a looming threat

Bezos never mentioned antitrust or antitrust regulators in the letter, but as government officials take increased note of the power and amount of data being held by large tech companies (and presidential candidate Sen. Elizabeth Warren has indicated she wants to break up Amazon and other companies) he definitely started building a defense.

“Third-party sellers are kicking our first party butt. Badly.” he wrote, pointing to the rise in physical gross merchandise sales on Amazon, which now stands at 58%. This led to a discussion about how Amazon had invested in selling tools and the Fulfillment by Amazon and Prime membership programs. So it might have been easy to shrug that one off.

A bit later, though, Bezos stressed “Amazon today remains a small player in global retail”—an odd claim for a company that reported nearly $142 billion in product sales last year.

“Multibillion-dollar failures” are coming to Amazon

Amazon experiments with new products all the time. It bought Whole Foods. It’s experimenting with brick and mortar stores. It’s also working on a healthcare venture with JPMorgan Chase and Berkshire Hathaway and has signaled an interest in home robots.

Some of these experiments, Bezos warned, are going to be colossal failures.

“If the size of your failures isn’t growing, you’re not going to be inventing at a size that can actually move the needle,” he wrote. “Amazon will be experimenting at the right scale for a company of our size if we occasionally have multibillion-dollar failures.”

Seeking to ease any investor angst that line caused, he hastened to add “The good news for shareowners is that a single big winning bet can more than cover the cost of many losers,” pointing to Echo as an example.

Bezos issues a minimum wage challenge

Months after raising Amazon’s minimum wage to $15 per hour, Bezos challenged retail competitors to do the same—or surpass the company

“We decided it was time to lead – to offer wages that went beyond competitive,” he wrote. “We did it because it seemed like the right thing to do. Today I challenge our top retail competitors (you know who you are!) to match our employee benefits and our $15 minimum wage. Do it! Better yet, go to $16 and throw the gauntlet back at us. It’s a kind of competition that will benefit everyone.”

What he didn’t mention was in raising the minimum wage, Amazon also did away with employee incentive pay including monthly bonuses and stock option awards.

Look for more Amazon brick and mortar stores

In talking about the company’s successes, Bezos made a point to namecheck the brick and mortar stores that do away with checkout lines.

While he stopped short of saying the company plans to expand the footprint of those, Bezos did seem to lean that way.

“The reward has been the response from customers, who’ve described the experience of shopping at Amazon Go as ‘magical’,” he said. “We now have 10 stores in Chicago, San Francisco, and Seattle, and are excited about the future.”