"When it comes to sentiment indicators, one of my favorites is insider buying," says Mike Burnick, editor of Global Market Investor.

The advisor is intrigued by insider buying in the financial sector -- particularly among regional banking stocks. He explains, "The insiders are buying with both hands. Now's the time to go long." Here, he looks at the KBW Regional Bank Index ETF (ASE: KRE).

"U.S. corporate insiders are now buying more of their own shares than they're selling for the first time since 1995. Nearly 2,000 insiders at NYSE listed companies are snapping up shares - while total buys beat out sells by 1.44 times.

"There are many reasons to sell, but there's really only one reason to open your wallet and buy stock... you think it's dirt-cheap and likely headed much higher in price.

"This insider buying is taking place all across corporate America, but it's especially significant in the beaten-down banking sector. Stock buying by insiders at banks, consumer lenders and insurers in the S&P 500 index jumped recently to the highest level in 12 years.

"That's the strongest 'buy signal' I've seen for banks since the aftermath of the Savings & Loan crisis. This aggressive buying has occurred even as bank shares slide into a black-hole of mounting subprime mortgage losses. Insiders are in the best position to know how well their businesses are performing.

"This bullish 'sentiment' sign forced me to take another look at the beaten down banking sector, and I like what I saw... particularly in the regional banks.

"The regional banks haven't suffered nearly the magnitude of subprime losses that are hitting the big money center institutions. That's because most regional banks stick to their knitting, the simple business of borrowing short and lending long. They never got wrapped up in collateralized debt obligations and other such exotica.

"Regional banks earn the bulk of their profits by borrowing money at low short term interest rates and making loans at higher rates. This means that as the Federal Reserve cuts short-term lending rates, profit margin at regional banks expand.

"Well guess what? The Fed is on the war-path right now, slashing rates. This is very good news for the regional banks, since their borrowing costs are falling dramatically. And that's likely to continue.

"There are many 'fundamental' reasons to like the regional banks right now too. They are trading currently at the lowest price-to-book value ratios in nearly 20 years. Regional banks offer investors rich dividend yields too - in many cases yields are much higher than 10-year U.S. Treasury bonds.

"IInvestors are so bearish on this sector, and the shares are so oversold, that this is in itself a bullish sign. And now the insiders are buying with both hands. Now's the time to go long regional banks. In my view, the best way to play it is the KBW Regional Bank Index ETF.

"There's no Citigroup in here, no Bank of America. These are true-blue middle-American regional banks, such as Hudson City Bancorp, Unionbancal, Sovereign Bancorp and Synovus Financial. These banks are far removed from the subprime credit crunch, but they've been sold in sympathy with the big banks.

"In other words, the KBW Regional Bank ETF is a real bargain. The regional bank stocks in this ETF trade at just over 13 times earnings - and yield over 6% -- that's more than most long term bonds pay in interest! I recommend you add shares of the KBW Regional Bank Index to your portfolio right away."