<div id="readability-page-1">It's not cool to peek over the shoulder of the smartest kid in your class to see what answer she gave for question No. 7 on a test. In the same spirit, you might peek to see what some of the richest investors have been buying -- and that's far less problematic. It's natural, in fact, to wonder where the supposed smart money is going. Here, then, are some relatively recent purchases made by some billionaires. I found them by checking their most recent 13F filings, which reveal purchases and sales. <div><img src="https://imageproxy.pbkrs.com/https://g.foolcdn.com/image//query-b3A9cmVzaXplJnVybD1odHRwczovL2cuZm9vbGNkbi5jb20vZWRpdG9yaWFsL2ltYWdlcy84MzI5OTEvYnVmZmV0dDgtdG1mLmpwZyZ3PTcwMA?x-oss-process=image/auto-orient,1/interlace,1/resize,w_1440,h_1440/quality,q_95/format,jpg" width="700" height="466" original-src="https://imageproxy.pbkrs.com/https://g.foolcdn.com/image//query-b3A9cmVzaXplJnVybD1odHRwczovL2cuZm9vbGNkbi5jb20vZWRpdG9yaWFsL2ltYWdlcy84MzI5OTEvYnVmZmV0dDgtdG1mLmpwZyZ3PTcwMA"/>Image source: The Motley Fool. </div> <h2>1. Warren Buffett</h2> Let's start with the most well-known of this bunch, Warren Buffett, who's famous for, among other things, growing the value of his company, Berkshire Hathaway (BRK.A -0.13%) (BRK.B 0.14%), by an annual average of around 20% for a whopping 60 years. In recent times, Berkshire's investment decisions have occasionally come from his investing lieutenants, Ted Weschler, and Todd Combs. As I write this, the latest 13F for Berkshire Hathaway reveals that the two biggest purchases in the quarter ending June 30 were UnitedHealth Group (UNH 1.91%) and Nucor (NUE 0.42%). UnitedHealth has seen its shares drop in the wake of multiple Department of Justice investigations and misconduct allegations (yikes!) -- not to mention the assassination of its CEO last year. Buffett is known for capitalizing on opportunities, and he or his lieutenants clearly viewed the market reaction as overreaction. Indeed, UnitedHealth has been offering promising news lately, including meeting its Medicare Advantage plan enrollment targets. Nucor, meanwhile, is a low-cost steelmaker, and a really big one at that. It's also been strategically savvy, as when it started producing building parts for data centers. Steel is a cyclical business, trending up and down depending on the economy, and Nucor is recently at a low point, offering a nice entry point for long-term believers. Both UnitedHealth and Nucor offer dividends, too -- recently yielding 2.6% and 1.6%, respectively. <h2>2. Bill Ackman</h2> Then there's hedge fund manager Bill Ackman, of Pershing Square Capital Management. In the same quarter, his biggest purchases by value were Amazon (AMZN -3.07%) and Google parent Alphabet. It's not hard to see why anyone might invest in either of those. (It's worth noting that Ackman is famous for running a concentrated stock portfolio, with only 12 holdings in his fund, which was valued at $13.7 billion in late June.) Amazon has multiple irons in the fire, most notably its massive marketplace and its dominant Amazon Web Services (AWS). Despite its huge size, recently valued at $2.5 trillion, it's still growing at a respectable clip, posting second-quarter results that featured net sales up 13% year over year. CEO Andy Jassy noted: &#34;Our conviction that AI will change every customer experience is starting to play out as we've expanded Alexa+ to millions of customers, continue to see our shopping agent used by many millions of customers, launched AI models like DeepFleet that optimize productivity paths for our 1M+ robots, ... and released Bedrock AgentCore to enable [AI] agents to be operated securely and scalably.&#34; Speaking of AI, Ackman recently had 45% of his portfolio in three AI stocks, and Alphabet is one of them. Alphabet's Google search is an 800-lb. gorilla, but many had wondered if AI would threaten its dominance. Instead, the company has been using AI as a tailwind, with search revenue growth actually accelerating recently. <h2>3. Stanley Druckenmiller</h2> Less well-known, Stanley Druckenmiller heads the Duquesne Family Office, which was valued at $4.1 billion mid-year. The fund's top purchases by value in the second quarter were Entegris (ENTG -0.04%) and Microsoft (MSFT -0.95%). Microsoft's growth potential is clear, as it encompasses the widely used Office productivity software, its Azure cloud computing platform, the popular Xbox gaming platform, and the Windows operating system, among other assets. It's another massive tech company that's somehow still growing rapidly, with its fourth-quarter revenue up 18% year over year and net income up 24%. It's another heavy investor in AI. Entegris is less well known, but it's a critical support company for the semiconductor industry, offering &#34;purification solutions and advanced materials.&#34; Druckenmiller is investing in a &#34;pick-and-shovel&#34; manner with this stock, as it's an adjunct to the fast-growing chip industry, with its offering critical for chip makers. These are just some of the investments that some financial bigshots made recently. If you search for 13F filings now and then, you'll find plenty more. Of course, always do your own digging into any portfolio candidate before buying. </div>

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Recent 13F filings reveal significant stock purchases by billionaires. Warren Buffett's Berkshire Hathaway bought UnitedHealth Group and Nucor, capitalizing on market overreactions. Bill Ackman invested in Amazon and Alphabet, focusing on AI growth. Stanley Druckenmiller's Duquesne Family Office acquired Entegris and Microsoft, targeting the semiconductor and tech sectors. These investments highlight the strategies of top investors in navigating market opportunities.

- Recent 13F filings reveal significant purchases by billionaires, including Warren Buffett, Bill Ackman, and Stanley Druckenmiller.  
- Buffett's Berkshire Hathaway invested in UnitedHealth Group and Nucor, capitalizing on market overreactions and offering dividends.  
- Ackman focused on Amazon and Alphabet, leveraging their growth potential, while Druckenmiller invested in Microsoft and Entegris, targeting the tech and semiconductor sectors.

6 Stocks Billionaires -- Such as Warren Buffett and Bill Ackman -- Recently Bought -- Including UnitedHealth and Amazon.com