The following commentary comes from an independent investor or market observer as part of TheStreet's guest contributor program, which is separate from the company's news coverage.NEW YORK ( Insider Monkey) -- Insider transactions are usually worth looking at. Though insider purchases or sells do not always send clear "buy" or "sell" signals, it is always a good starting point to choose which stocks to be analyzed. In this article, we are going to take a closer look at a few insider purchases reported to SEC during the last week. We selected a few notable insider purchases with large dollar amounts purchased and large number of shares purchased. We also focused on stocks with relatively large market caps (above $1.5 billion) because these have enough liquidity to absorb sudden surges in demand.