Google’s top executives have been selling their holdings non-stop for almost three and a half years, a trend that ultimately gained some attention from the market.

We have noted several times in the past how Google’s top people, CEO Eric Schmidt in particular, sold Google shares as rapidly as 10b5-1 plans could allow. Check out the last twelve months of Google sales: 398 sales of over a million shares combined. Zero purchases.

It only took a couple of years for someone in the investment world to figure out that, hey, they sure seem to be selling a lot of shares here. The Wall Street Journal cited Jonathan Moreland, research director at InsiderInsights.com and subadviser to Ladenburg Thalmann Asset Management, as someone who publicly commented on these transactions:

Mr. Moreland said the nearly constant selling of shares by insiders of the Mountain View, Calif., Internet giant, along with the utter lack of open-market purchases, had always bothered him, but the company’s soaring stock price — until November — had persuaded him not to short the stock.

“And when that momentum finally starts breaking down, see what the insiders do,” Moreland said. “And if they continue to sell, that’s when you act on the signal.”

He said he was more interested in sales by lower-level executives, and the lack of insider purchases.

“So many of these insiders have been so anxious to sell or exercise their options, and so unwilling to hold much of anything long, and that’s a particular red flag to me,” he said.

Moreland also admitted to feeling sheepish about acting on what was going on by shorting some shares of the “stock-market darling.” Once he got over his misgivings, Google insider transactions rewarded him with a 27.4 percent return on his shorting.

Google closed on March 4th at $447.70, well off the 52-week high of $747.24. We will be surprised if it ever gets near that high again.