It’s advice you hear time and again from investing pros: Don’t try to time the stock market.

No one knows when the market’s going to drop, by how much, and how long a recovery will take. Instead, investors should buy in at regular intervals — an investing tactic known as dollar-cost averaging — to buy when the market is both up and down. As markets tend to rise over the long term, it’s a winning recipe.

But one money manager for high-net-worth clients thinks investors can have it both ways, and he’s got a strategy he deploys to prove it.

Jeffrey Fratarcangeli, the founder of Fratarcangeli Wealth Management, says he uses a two-pronged approach to investing for some of his clients, who have an average net…