BOSTON (Reuters) - Fidelity Investments has slashed its estimated valuation of technology companies Cloudera and Dropbox, a report on Wednesday showed, in the latest indication of concern over the high prices of startups that have raised many millions from private investors, but delayed going public.

A billboard displays the logo of Snapchat above Times Square in New York March 12, 2015. REUTERS/Lucas Jackson

Boston-based Fidelity, which has become one of the largest investors in pre-IPO companies through mutual funds that include the $100 billion-plus Contrafund FCNTX.O, marked down its stake in big data software company Cloudera by nearly 37 percent, the mutual fund disclosed in its monthly holdings report.

California-based Cloudera, backed by Fidelity as well as high-profile investors including Google Ventures and T Rowe Price, has a $4.1 billion valuation in the private market. Investors have anticipated its IPO for over a year.

Fidelity’s monthly reports offer a glimpse into investor concern over the sky-high valuations of some private companies that have over the last few years enjoyed a seemingly unlimited stream of financing from venture capitalists, mutual funds and hedge funds.

Now many of those companies are struggling to meet growth targets, and the volatile stock market has made an initial public offering an unfavorable exit route.

Fidelity also slashed the estimated worth of cloud-storage company Dropbox by almost 20 percent. Investors have long expected that company to go public, but it has struggled with competition and profitability, people close to the company have said.

Fidelity previously marked down - and marked up again - the value of its stake in Dropbox. The company is estimated to be worth about $10 billion in the private market.

Zenefits, the human resources software startup that has been beleaguered by state investigations for flouting insurance laws, was marked down by more than 24 percent. Fidelity last year slashed its Zenefits stake by about 48 percent.

But the mutual fund is still bullish on some startups, boosting its stake in free mobile messaging app Snapchat in February despite recent concerns the company is struggling to gain traction with advertisers.

Fidelity’s Blue Chip Growth Fund reported holding $27.64 million worth of Snapchat Series F shares at the end of February, compared with $17.03 million at the end of January.

The increase likely reflects both more Series F shares being bought for the fund and an increase in the estimated value of those shares from the previous month. Fidelity declined to comment on share count and valuation details.

Reuters reported earlier this month that Snapchat had raised $175 million from Fidelity. It was a so-called flat round that did not move the company’s $16 billion valuation.