Famed investor Warren Buffett has down played the prospects for big deals this year, in what will prompt many investors to pause for thought.
And the billionaire appeared to fault US President Donald Trump for taking too much credit for the country's economic growth.
Mr Trump often takes credit for upbeat news on the economy and stock market, sometimes tying them to his economic policies.
Mr Buffett, who supported Democrat Hillary Clinton in her 2016 White House run, said no one person should claim credit when things go well. "It is beyond arrogance for American businesses or individuals to boast that they have 'done it alone'," Mr Buffett told shareholders.
The doyen of investing said valuations for businesses were sky high.
He said in his annual letter to shareholders that he was hunting for "an elephant-sized acquisition", but was not optimistic about getting it done.
The billionaire investor said the prospects of landing a mega-deal for his Berkshire Hathaway conglomerate were "not good", because "prices are sky-high for businesses possessing decent long-term prospects".
It is a problem for the Berkshire chairman and chief executive, whose company is sitting on $112bn (€98.54bn) in cash and other low-returning assets that it has been struggling to invest for years.
"In the years ahead, we hope to move much of our excess liquidity into businesses that Berkshire will permanently own. The immediate prospects for that, however, are not good: Prices are sky-high for businesses possessing decent long-term prospects," Mr Buffett wrote.
"That disappointing reality means that 2019 will likely see us again expanding our holdings of marketable equities. We continue, nevertheless, to hope for an elephant-sized acquisition."
The prospect of such a deal, "causes my heart... to beat faster", the 88-year-old said.
But Mr Buffet said he would not get caught short of cash that he could use should market conditions deteriorate.
Some of Mr Buffett's transactions over the last decade or so have included complex deals with distressed companies, including in the aftermath of the global financial crisis.
The Omaha investor has also been snapping up more shares of his own stock. Berkshire bought back about $1.3bn (€1.14bn) of its common stock in 2018, the company said. But Mr Buffett slammed corporate bosses who buy stock back when prices are lofty.