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 Robeco Investment Management, which is a U.S.-focused subsidiary of major Netherlands-based financial institution, Rabobank. It has three primary divisions: Boston Partners (value equity), Sage Capital (multi-manager strategies), and Weiss, Peck & Greer (fixed income, equity and alternatives). It has been in the news a bit lately, with Rabobank trying to sell its investment management business and some suitors, such as Australia's Macquarie Group, not wanting all of the U.S.-based business.

Robeco Investment Management touts its flat management structure and focus on value equity investing. The company's reportable stock portfolio totaled $36.3 billion in value as of June 30, 2013.

Interesting developments
So what does Robeco's latest quarterly 13F filing tell us? Here are a few key details.

The biggest new holdings are Marathon Oil and Prudential Financial. Other new holdings of interest include Pitney-Bowes (NYSE:PBI), which just posted estimate-topping earnings, along with a drop in revenue and lowered guidance. It's also selling its management service business for $400 million, as it focuses more intently on its core operations. Pitney-Bowes has been attracting income-seekers with a double-digit dividend yield, but it recently slashed that in half. Its remaining 5.2% yield is nothing to scoff at, though. Its legendary postage-meter business has not been thriving amid proliferating digital communications and it does carry considerable debt.

Among holdings in which Robeco Investment Management increased its stake was Windstream (NASDAQ:WIN), which has been known as a rural telecom company, but has been shifting its focus more toward broadband service and business customers. Still, it remains significantly a landline company, though one with a dividend yielding more than 12%! Its earnings have been shrinking in recent years, but it's still generating solid free cash flow. Its investments in new revenue streams may ultimately pay off, too.

Robeco Investment Management reduced its stake in lots of companies, including the KeyCorp (NYSE:KEY) bank, which has been performing well, but not perfectly (its net interest income is above average, for example). KeyCorp has drawn some negative attention for its overdraft fees, too. The company has partnered with other big banks to develop mobile banking, and has just sold off its Victory Capital Management business. Its latest quarter featured a drop in earnings due to downsizing costs and acquisitions.

Finally, Robeco's biggest closed positions included insurer Unum and Smithfield Foods. Other closed positions of interest include Nuverra Environmental Solutions (NYSE:NES) and VeriFone (NYSE:PAY). Nuverra, until recently known as Heckmann, provides water-related services and chemicals for the growing (but controversial) fracking method of gas extraction. (It handles waste disposal, too, among other things.) Heckmann posted disappointing earnings for its first quarter and recently warned that its second quarter won't be pretty, either, in part due to bad weather. On the plus side, Nuverra has partnered with Halliburton to recycle fracking water.

VeriFone has seen its stock nearly halved over the past year, as it has repeatedly posted disappointing operational results. Indeed, its June earnings report sent shares down some 20%. Several insiders have recently bought hundreds of thousands of dollars' worth of shares, though, which is rarely anything but a positive sign. The company's recent contract with China is promising, too, and with growing free cash flow and a forward P/E ratio near 11, VerFone is seen as attractive by some, and as a possible acquisition target. Bears worry, though, about competition (especially in the mobile realm), and don't like that its operating and net margins have been falling lately.

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.

Longtime Fool contributor Selena Maranjianwhom you can follow on Twitter, owns shares of Windstream. The Motley Fool recommends Halliburton. The Motley Fool owns shares of KeyCorp and Nuverra Environmental Solutions and has the following options: long January 2014 $4 calls on Nuverra Environmental Solutions and short January 2014 $3 puts on Nuverra Environmental Solutions. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.