Thanks to stubborn fund managers and record corporate buybacks, U.S. stocks remain near all-time highs even as money continues to trickle out of U.S. shares and into international equities.

For the eighth week in a row, long-term mutual funds saw more money flowing out of U.S. stocks and into international stocks, according to the Investment Company Institute. Even so, the Dow Jones Industrial Average DJIA, -0.87% , the S&P 500 index SPX, -1.11% , and the Nasdaq Composite Index COMP, -1.07% are all less than 2% off their records and are all up for the year to date.

Meanwhile, European stocks SXXP, -0.66% are up close to 16% this year.

For the week ended April 22, U.S. stocks saw $3.4 billion in net outflows from long-term mutual funds, while international stocks saw $6.53 billion in inflows, the ICI estimated. For the year to date, net outflows for U.S. stocks are $13.79 billion, while inflows for international stocks are $41.12 billion.

Those figures, however, don’t count exchange-traded funds. In April alone, mutual funds and ETFs that focus on international stocks saw $31.8 billion in net inflows, while U.S.-focused funds and ETFs shed $15.4 billion, according to TrimTabs Investment Research.

‘Seller’s strike’

It’s possible that while individual U.S. stocks are being shed due to concerns about fundamentals, money managers are largely holding on to large positions in light of record highs.

“This is a ‘seller’s strike’—stocks may look expensive but large holders see the market at near/new highs and decide to hold off any sales,” said Nicholas Colas, chief market strategist at Convergex, in emailed comments. “There is an old trader’s saying—‘Never short a new high.’ Selling a position as a large money manager is like shorting it.”

Also, quantitative-easing measures by the European Central Bank and the Bank of Japan are also attracting new money to international stocks, Colas said in a recent note.

More money, fewer stocks

If money is flowing out of domestic stock funds, what’s holding up U.S. equity prices? Much of the support comes from corporate stock buybacks, said Winston Chua, an analyst at TrimTabs, in emailed comments.

“The short answer is that existing companies are repurchasing their shares and decreasing the amount of supply in the market, thus driving up prices,” Chua said. “More money is chasing fewer shares of stock.”

Those buybacks are on track to hit a record this year, which might not be the best use of corporate cash, Goldman Sachs said in a recent note. In 2014, the amount of money spent on corporate buybacks hit their highest level since the financial crisis, with about a fifth of the S&P 500 significantly reducing their share counts.

Then again, fund outflows for U.S. stocks and higher prices isn’t anything new, said Dan Greenhaus, chief strategist at BTIG, in emailed comments

“Let’s not forget that U.S. stocks have more or less had outflows since the first day of the recovery,” Greenhaus said. “It hasn’t prevented stocks from moving higher in the past so I’m unsure why outflows should prevent stocks from going higher in the present.”

According to ICI data, U.S. stocks have seen net outflows of $451.07 billion from long-term mutual funds since March 2009, while international funds have seen $370.62 billion in net inflows.