The balance of shares bought on credit rose for the fifth straight week last week, although the pace of increase slowed visibly.
The outstanding balance of long-margin positions on the Tokyo, Osaka and Nagoya stock exchanges stood at 1.84 trillion yen at the end of the week, up 17.58 billion yen from the previous week, according to an industry report.
The jump was less than half the 36 billion yen gain registered a week earlier, reflecting increasing caution among market players.
Tokyo stock prices remained in a corrective phase through much of the week, amid lingering fears over economic and corporate earnings prospects.
Listed companies rolled out their earnings results for the year to March 31, releasing downbeat earnings forecasts for the year ahead.
In terms of volume, the balance of margin-buying stood at 2.95 billion shares, down 5.38 million shares, marking a second week of decline.
The balance of shares sold short, on the other hand, fell 1.08 billion yen to 899.25 billion yen, posting a turnaround from an 18.6 billion yen increase the previous week.
In terms of volume, however, the balance of short margin positions rose 18.37 million shares to 1.01 billion, reflecting a switch into low- and medium-priced issues, which have been favored by investors in recent weeks.
The long-short ratio rose to 2.04 from 2.02 in terms of value but fell to 2.91 from 2.97 in terms of volume.
The 225-issue Nikkei average ended the week at 13,430.22, up 166.38 points, or 1.3 percent, on the week.
But the key market gauge remained well below the year's closing high of 14,529.41, posted on May 7.