London, (Pal Telegraph) - Early last month, when the stock market tanked, they turned out in force yet again. It was a very hopeful sign. In early August insiders bought shares at an even faster rate than they did at the market lows in March 2009. Indeed, TrimTabs says it was the fastest rate since November 2008.

Reuters

Traders work on the floor of the New York Stock Exchange.

The buying slowed in late August, when the market rallied and shares became more expensive. You’d expect that.

But around Sept. 7 the rate collapsed — even though share prices were coming back down. You would certainly not expect that — unless something was up.

Biderman points out that the insiders are sitting on their hands even though many share prices are still down at the same levels as early August.

Data from InsiderScore, a specialist research firm, points to a similar conclusion.

Consider the smaller growth companies that make up the Russell 2000 Index RUT +1.40% . InsiderScore reports that honcho sentiment at these companies was very bullish just a few weeks ago. The people running these companies plunged into the market to buy up stocks in early August, when prices fell.

Today their share prices are no higher. But the insiders are no longer acting bullish.

And InsiderScore reports that the picture is similar for financial stocks, too.

What’s up?

The executives and their customers are back at their desks after the summer vacations. They’ve had a chance to look at the forward order books.

Or maybe they’re just worried about the big picture.

Greece. China. The U.S. economy. The budget. Any number of things could cause the stock market to throw a wheel.

Biderman blames uncertainty. “It looks to me that insiders are uncertain as to what’s happening,” he says.

Markets rallied yesterday on “rising hopes” (again) about Europe. They sank Monday in “growing fears” about Europe. And so it goes. If I wanted to commit myself to stocks at these levels, I’d rather see the insiders doing the same.

Brett Arends is a senior columnist for MarketWatch and a personal-finance columnist for the Wall Street Journal.