The game has changed in the last year or so, with markets now driven by politics instead of central banks, according to a strategist at a widely followed investment group.
Christopher Wood, an equity strategist at investment group CLSA, said Tuesday that central banks have been the key driver of markets in the last decade, and the "great thing" about them was that they were "doing their best to be entirely predictable."
Speaking to CNBC's Akiko Fujita at the 2018 CLSA Investors' Forum in Hong Kong, he said: "In the last 12 to 18 months, the game's changed. The central banks are no longer the key driver ... the key driver is politics."
"The risk but also the opportunity is that politics are much less predictable than the central banks," he added. "The only chart I have relating to politics was on Donald Trump's popularity."
This year, there have been several geopolitical developments, such as the U.S.-China trade tensions, as well as U.S. pressure on North Korea to denuclearize, which included a meeting between U.S. President Donald Trump and North Korean leader Kim Jong Un.
On the rapid growth in the U.S. economy, Wood said the cyclical momentum may have peaked last quarter, but not before having an "extraordinary impact."
"The dominant phenomenon in the markets this year is the extraordinary impact on the U.S. stock market and the U.S. economy ... driven by U.S. corporate tax cuts, which has been dramatic. You can see the surge in earnings ... the collapse in corporate tax revenues ... the dramatic surge in small business confidence ... and most spectacularly, you can see it in the surge in share buybacks," he said."
In the first quarter alone, multinational enterprises brought home about $300 billion of the $1 trillion held abroad, according to a recent Federal Reserve study. A good chunk of that went to share repurchases. For the top 15 cash holders, some $55 billion was used on buybacks, more than double the $23 billion in the fourth quarter of 2017.
Goldman Sachs economists predicted that the total buybacks from all companies in 2018 could exceed $1 trillion.
— CNBC's Jeff Cox contributed reporting to this story.