Editor's note: A previous version of this article misstated the values of CalPERS' pension fund and stock portfolio. The Motley Fool regrets the error.

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 the California Public Employees Retirement System (often referred to as CalPERS), one of the biggest and most prominent pension funds. It serves more than 1.6 million public employees, retirees, and their families.

The company's reportable stock portfolio totaled $158 billion in value as of Feb. 28. Fifty-four percent of its investment portfolio was recently in public equity, with another 11% in private equity, 15% in income investments, and 9% in real estate, among other categories.

Interesting developments
So, what does CalPERS' latest quarterly 13F filing tell us? Here are a few interesting details.

Some new holdings of interest include Intercept Pharmaceuticals (NASDAQ:ICPT) and National Bank of Greece SA (OTC:NBG.DL). Intercept Pharmaceuticals has seen its shares surge more than 600% over the past year, and while some fear overvaluation, others still see great potential. Intercept recently reported very encouraging results from late-stage trials of a drug to fight primary biliary cirrhosis, a liver disease that has no very effective treatment yet. The company recently issued 1 million new shares to generate needed funds.

The National Bank of Greece has averaged annual losses of 30% over the past decade, so it may not be a big surprise that the bank, having been found by a stress test to be short on capital, is raising more than $3 billion by issuing more shares. That's leading many to worry about dilution, of course. The bank posted a profit in 2013 and sold assets, too, in order to raise funds.

Among holdings in which CalPERS increased its stake were Companhia Energetica de Minas Gerais (NYSE:CIG) (also known as Cemig) and Walter Energy (OTC:WLTGQ). Cemig's fans like that the electric company is based in the huge market of Brazil, where power usage is growing. They also like that the company is diversifying via investments in water and wind power, among other things. It's also improving its distribution and making aggressive expansion plans. Bears worry about rising costs, though, as well as interference from Brazil's government affecting profitability. The company's 2013 revenue rose 3.5% over 2012 levels.

Walter Energy is a pure play in metallurgical ("met") coal, which is needed by the steel industry. It has been having some rough years lately, with its stock falling by more than 50% over the past year. It slashed its dividend by 92% last year to help it address its heavy debt load, and recently it has been idling some of its mines -- and their eventual sale is not out of the question, either. There's an oversupply in the met coal industry, which is depressing prices and hurting many coal companies -- and now natural gas is replacing coal in some steel production, too.

CalPERS reduced its stake in lots of companies, including Ambarella, (NASDAQ:AMBA), a semiconductor company focused on video with offerings such as high-quality sports cameras and surveillance cameras. With the GoPro company doing well and planning to go public, Ambarella's prospects are strengthened, as its products are found in GoPro cameras. Ambarella's last quarter was strong, featuring revenue up 27% over year-ago levels and GAAP EPS up 38%, with demand strong in China, among other places.

Finally, CalPERS's biggest closed positions included Life Technologies and Voya Financial.

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. 13F forms can be great places to find intriguing candidates for our portfolios.