Famed market timer Marty Zweig is closing the book on 26 years of investment advice. In a heartfelt letter to subscribers of The Zweig Forecast this week, the author has disclosed his desire to focus his energies on the $7 billion in partnerships and mutual funds he runs.

He explained that when he began the newsletter in 1971, he had no money under management. "The Forecast was my primary effort and I gave it my all. But in recent years the demands on my time and energies have moved increasingly toward money management which provides at least 98% of my income."

Zweig's letter says he has asked Richard Russell, author of the Dow Theory Letters, to step into his shoes. Current subscribers will begin receiving that letter following Zweig's final issue of the Zweig Forecast in January.

In early November, Zweig told Barron's he was bullish in the wake of the events of Gray Monday. He said, "I am not predicting either another 182% gain, or another Crash of '29," but continued: "Could you still get a couple of 15% years, or something like that, out of the market? Yes. You might be able to." But he added that he "had no idea" how things would go. "I am positive right now. I could change my mind entirely in a matter of weeks if conditions change."

This year his open-end funds are underperforming. His Strategy fund is up 12.9%, his Appreciation fund up 19.1% and his Growth & Income fund up 17.1%. The S&P 500 is up 28.2%.

We will update this story later today.