Every quarter, many money managers must 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 Kahn Brothers, chaired by Irving Kahn, who will soon turn 108. The firm was founded in 1978, but Kahn's investing experience began far earlier -- he was a teaching assistant for Benjamin Graham, who was the key mentor of none other than Warren Buffett.

Kahn Brothers invests "primarily in undervalued and often unpopular securities that present both a margin of safety and attractive prospects for capital appreciation." The company adds that "in the tradition of Graham and Dodd, our investing discipline continues to stress three key words: margin of safety," and notes that "we align our interest with our clients' interest, purchasing the same securities for them that we do for ourselves. 'We eat our own cooking.'"

Kahn Brothers' reportable stock portfolio totaled $638 million in value as of Sept. 30, 2013.

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

The biggest new holdings are BlackBerry (NYSE:BB) and Straight Path Communications. Smartphone titan of yore BlackBerry has fallen on hard times, but for some investors it has fallen so far that it's now attractive. New CEO John Chen, who helped turn Sybase around, presents a promising change. For a while it looked like the company might be taken private, or that its assets would be sold off, but for now it's remaining an ongoing public concern. Deutsche Bank analysts recently upgraded BlackBerry from sell to hold, but it remains quite a speculative proposition, with shrinking free cash flow.

Among holdings in which Kahn Brothers increased its stake were New York Community Bancorp (NYSE:NYCB) and oil giant BP (NYSE:BP). New York Community Bancorp, known for prudent management of credit risk, has grown by an annual average of 28%(!) since its IPO in 1993. It has been buying other banks and expanding its commercial and industrial lending business. The bank's third quarter featured estimate-topping earnings (albeit lower than those from a year ago) and improving credit quality. Some see the bank's sizable multifamily loan portfolio as a particularly promising asset, offering refinancing-related income. New York Community Bancorp stock sports a whopping 6.2% dividend yield.

BP is appealing, with a 4.6% dividend yield, but as my colleague Tyler Crowe summarizes, "BP has spent approximately $42 billion for everything related to the [Gulf of Mexico oil] spill, and it is on the hook for another potential $55 billion for charges from both the Clean Water Act and local and state government claims." BP has sold many assets to generate needed funds, but it's also retained a promising project portfolio, is addressing debt, operating more conservatively, and upping its dividend. On the other hand, drilling costs have been rising, and the company's hydrocarbon production has slipped.

Kahn Brothers reduced its stake in companies such as First Niagara Financial Group (NASDAQ: FNFG) and Bristol-Myers Squibb (NYSE:BMY). First Niagara Financial Group, yielding 2.9%, is trading near a 52-week high. It has more than tripled its asset base since the financial crisis, though it hiked its share count to do so, which dilutes share value. Meanwhile, the company has been managing its credit risk well, and should benefit from rising interest rates. It's poised for a solid turnaround, and with a recent P/E ratio of 15.5 and a forward P/E of 13, is worth a look.

Bristol-Myers Squibb posted revenue up 9% in its last quarter (over year-ago levels), and topped analyst expectations. Its skin-cancer drug Yervoy has been performing well, and it recently reported promising results an arthritis drug and for its PD-1 inhibitor nivolumab, which treats nonsmall cell lung cancer. Meanwhile, Bristol-Myers Squibb is an early mover against hepatitis in Japan, filing a treatment approval application before some key competitors. Morgan Stanley has upgraded the stock to outperform and hiked its price target by 33%. Still, bears worry about patent expirations (which plague every pharma company) and don't like that its newly approved blood thinner, Eliquis, isn't selling too briskly. Bristol-Myers Squibb stock yields 2.7%.

Finally, Kahn Brothers' biggest closed positions included Dime Community Bancshares and TCF 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.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.