NEW YORK ( TheStreet) - Insider trading is most profitable when several insiders buy around the same time. Academic studies have shown that insider purchases beat index funds by more than 7 % per year when there are several insiders purchasing.

Last week we published the list of companies with at least 3 insiders buying . Here is how those 7 stocks performed:

1. Bank of America ( BAC) was up by 8.3% vs. 1.0% for SPDR S&P 500 ( SPY) during the past week. The insider who paid $11.3 for BAC shares had a 12% return. We were right when we stated that this is a good point to monkey BAC insiders.

2. Versar ( VSR) returned 4% during the past week, better than SPY's 1% return. However, it's a very illiquid stock, so monkeying wouldn't have yielded much in actual dollars.

3. Rimage ( RIMG) went up by 4.2% beating the market by more than 3 percentage points in one week.

4. Harris Interactive ( HPOL) jumped 38.6% for a phenomenal return. However, the stock had a daily trading volume of only 30,000. Naturally, it isn't really possible to build a meaningful position in this stock (unless one has a very small portfolio).

5. Jamba ( JMBA) went down by 0.5% during the past week. However, the last insider transaction had a 10-day return of 5.9%. The stock jumped by more than 6% in three days following the insider purchase and then leveled off.

6. Citigroup ( C) rose 6.1% during the past week, beating the market averages. Last week we inferred that these insider purchases in banking stocks imply that the banking sector is undervalued in general. During the same time period KBW Bank ETF ( KBE) also went up by 5.9% supporting our claim.

7. Buckeye Technologies ( BKI): Buckeye went up by 3.4% during the past week. This one also managed to beat the market averages.

Overall, the consensus criterion beat passive investing by 6-1 during last week.

Excluding Versar (returned 4%) and Harris (returned 38.6%), the average return for this portfolio was 4.3% during the past week. Of course, this is just a very small sample and does not prove or disprove the credibility of monkeying insider purchases.

Insider Monkey, your source for free insider trading data , will share very recent academic studies with you, so that you can do your own research. We will keep providing weekly updates on stocks insiders buy like crazy, although it might be better to follow them in real-time if one is monkeying insider transactions.

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