NEW YORK – Imagine the dilemma of having so much cash in your bank account that you didn’t know what to do with it.

This is of course a pipe dream for the average American, but is now reality for the country’s biggest corporations. The industrial companies that make up the Standard & Poor’s 500 index – which excludes financial, transportation and utility companies – have a staggering $643 billion in cash and equivalents.

Wall Street analysts remain unsure how companies will spend this record hoard. Even an unprecedented $500 billion of stock buybacks over the past six quarters have failed to stop companies from building lofty amounts of cash on hand.

“We’re in a time that is out of whack with all historical numbers,” said Howard Silverblatt, equity market analyst at Standard & Poor’s. “People are demanding why corporations need so much cash, what are they going to do with it? In spite of stock buybacks, dividends and acquisitions, this cash is still going to take a while to spend.”

The money tucked away in corporate coffers has now gotten to the point where it’s having a major impact on quarterly earnings, with S&P reporting that income earned on the interest rose 37.9 percent in 2005 and is expected to increase another 64 percent this year.