NEW YORK, Sept. 23 (UPI) -- A new report shows billionaires are hoarding hundreds of millions in cash as a result of their reservations about investing in the markets.

The 2014 Billionaire Census from Wealth-X and UBS revealed billionaires are keeping an average of $600 million -- about 19 percent of their net worth -- in cash as they wait for a more stable outlook in the markets.


"This increased liquidity signals that many billionaires are keeping their money on the sidelines and waiting for the optimal moment to make further investments," read the report.

One year ago, billionaires only kept about $60 million each in liquid funds. Real-estate holdings only average about $160 million -- about one-fifth of cash assets -- of billionaires' wealth.

The urge to keep their money under the proverbial mattress stems from grim recession memories when the wealthiest took some of their biggest hits. This strategy could backfire as inflation threatens the value of the dollar, said Simon Smiles, chief investment officer for Ultra High Net Worth at UBS Wealth Management.

"The apparent safety of cash, reinforced by the painful psychological experience of the 2008-09 global financial crisis and the subsequent troubles within the European Monetary Union, likely reinforces the tendency to favor this cautious allocation strategy," he said in the report.

Millionaires are squirreling away cash as well with about 20 to 30 percent of their assets liquid. They have been holding their wealth in cash after feeling they missed the boat to invest well in 2012 and 2013.

"It's the combination of many people having been under-invested in equities and under-invested in wide risk assets having seen rallies and missed those rallies," he said. "Things are no longer cheap, and it's emotionally hard to get invested now."