Every quarter, many money managers have to disclose what they've bought and sold, via 13F filings. Their latest moves can shine a bright light on smart stock picks.

Today let's look at activist investment firm Relational Investors. Based in San Diego and run by Ralph Whitworth, the company has made a name for itself by agitating for changes at many major corporations, such as Genzyme and Home Depot. (At Home Depot, Whitworth called for the company to exit its commercial building supply business.)

The company's reportable stock portfolio totaled $5.9 billion in value as of March 31, 2012.

Interesting developments
So what does Relational Investors' latest quarterly 13F filing tell us? Here are a few interesting details:

There was just one new holding, apparel retailer Abercrombie & Fitch (NYSE: ANF), which has seen its stock fall 53% over the past year. Revenues have been rising, but earnings have not followed suit lately, and shareholders have been dismayed by a series of embarrassing corporate moves. Still, some think the stock is oversold, with its P/E ratio nearly half of its five-year average and its forward P/E at 7.

Among holdings in which Relational Investors increased its stake were PepsiCo (NYSE: PEP) and PMC-Sierra (Nasdaq: PMCS). Relational nearly doubled its stake in PepsiCo, to almost $600 million. It's still far from being one of the top 10 institutional owners, but PepsiCo has taken notice and has met with Whitworth, who has suggested splitting up the company into a faster-growing snack business and a slower-growing beverage one. In a sign of PepsiCo's plans, the company has created the position of Chief Design Officer (CDO) and filled it with the former CDO of 3M, charging him with helping expand PepsiCo's top brands.

Relational Investors sees networking and data-storage-equipment chip-maker PMC-Sierra not growing its sales as fast as it could and may push the company to trim its business divisions or perhaps even merge with another company. At PMC-Sierra's 2012 shareholder meeting, management waxed bullish about the company's prospects due to the growth of digitization "of everything," smartphones, cloud computing, and video streaming. It's also aggressively buying back its own stock.

Relational Investors reduced its stake in a lot of companies, including MetLife (NYSE: MET), which has suffered in part due to flagging interest domestically in life insurance. The company aims to combat that by, among other things, focusing more heavily on fast-growing emerging markets and shedding less-productive businesses. To some investors, it seems quite attractive now, with a current and forward P/E of just five and a dividend yield around 2.5%.

Finally, Relational Investors unloaded several companies, such as Freeport-McMoRan Copper & Gold (NYSE: FCX). There's a lot to like about the company, though, such as its reduced debt level, its ability to benefit from rising infrastructure spending as the global economic recovery gains traction, and the fact that it's putting recent labor problems behind it. A rising copper price would also help the company.

We should never blindly copy any investor's moves, no matter how talented the investor. But it can be useful to keep an eye on what smart folks are doing, and 13F forms can be great places to find intriguing candidates for our portfolios.

If industrial stocks interest you, check out our special free report, "3 Stocks to Own for the New Industrial Revolution," which details a new technology that might shift the "Made in China" trend back toward "Made in America."