Mr. Letteri is one of a growing number of venture capitalists rooting for a market dip to calm the overheated start-up scene. For the past few years, Silicon Valley tech start-ups have been awash in a stream of cash that has allowed them to expand quickly and sell or go public at high valuations. Yet that drove up the costs of deal making for venture capitalists, who often prefer to invest in young companies at lower prices in the hopes of making a bigger return later.

Now some of these investors may get their wish for a market decline. Stocks tumbled late last year, led by tech giants such as Facebook and Apple, amid fears of slowing economic growth and a trade war with China. And so far this year, the stock market has swung wildly, whipsawed by confusing signals including Apple’s disappointing iPhone sales in China and American employers adding more jobs than expected last month.

While it takes time for choppiness in the stock market to ripple out into the start-up market, many venture investors are already preparing for a downturn. Some are setting aside money to pounce on investments and are preparing to write bigger checks with the expectation that new investors who flooded in in recent years will flee. And they are keeping closer tabs on companies that were too expensive to invest in last year.

“We definitely want to take advantage of a market downturn,” said Sandy Miller, a venture capitalist at IVP who projects that start-up valuations will fall by 10 percent to 40 percent this year. He said his Silicon Valley venture firm has set aside “meaningful reserves” to do more deals and to put more money into companies it has already invested in, though he declined to specify an amount.