LONDON -- As you may already know, Berkshire Hathaway (NYSE: BRK-A) (NYSE: BRK-B) CEO Warren Buffett has spent more than $1 billion buying the shares of one of the U.K.'s most successful large caps.

Clearly he thinks there are bargains to be had within Britain's elite FTSE 100 (INDEX: ^FTSE) index -- and my research suggests there are plenty more buying opportunities for smart American investors prepared to look across the Atlantic.

So as you wait for the Dow Jones Industrial Average (INDEX: ^DJI) to open this morning, I'd encourage you to consider the American depository receipts of Aviva (NYSE: AV) for your portfolio.

Screen the FTSE 100 shares on a simple P/E and dividend-yield basis, and one of the names at or near the top of both lists should be U.K. insurance giant Aviva.

Whether this makes it a dangerous value trap due to the eurozone crisis or simply a screaming bargain depends on your viewpoint. But for me, it's most definitely the latter. And value-based investors need the courage of their own convictions in going against the herd.

To put some specifics on what are unfeasibly generous investing figures: At the current ADR price of $9.60, Aviva's expected P/E for this year is about 5, while the dividend yield is expected to be 9%.

Clearly, these figures don't make a lot of sense, so either the share price will in time rise in line with the market, or the market knows something that neither I nor a veritable army of brokers is aware of.

Personally, with their forecast yield of 9%, I don't much care if the shares rise or stay flat. I'm simply looking to the opportunity of reinvesting the dividends to compound the overly generous yield for the future.

I must admit Aviva did cut its annual dividend three years ago, which I reckon makes another cut less likely, but not impossible, of course. Within the group's 2011 final results, the dividend was raised 2% on the previous year, making the historical yield just greater than 8.6%.

Meanwhile, net tangible assets account for 93% of the current $14 billion market cap.

The whole of the U.K. insurance sector is a contrarian investment in itself at the moment -- and Aviva is one of the most contrarian within that sector, as illustrated by its valuation figures. This kind of fear, though, creates valuation anomalies.

Aviva has done a lot of things right in recent years, deleveraging and reorganizing its businesses while increasing business in the markets where it sees the most potential.

However, that still wasn't enough to see off a recent revolt by institutional shareholders when the majority refused to back the company's boardroom pay policies. The institutions did back the boss personally, with 95% voting to re-elect him as CEO, but he still fell on his sword.

This doesn't change the valuation case, though. I'm convinced Aviva is too cheap on all conventional measures, so in my view it's time to follow Buffett's advice and be greedy while others are fearful.

Let me round off by adding that this special Motley Fool report, "8 ADRs Held By Britain's Super Investor," reveals the FTSE 100 stocks favored by U.K. investment legend Neil Woodford. You may be attracted to the ADRs of the companies he owns, too. The report is free.

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