Buying fever swept the Frankfurt stock market again yesterday as West German and foreign investors paid record prices for the second day running.

The Commerzbank index of 60 leading stocks reached 1,475, easily surpassing Wednesday's record level of 1,462.4. The index is up 32.66 percent since the start of 1985.

Stock-market analysts with the country's leading commercial banks are unanimous that the potential for further gains could stretch into 1986. The rise is already one of the strongest in West Germany since the end of World War II.

Only a sudden collapse in the value of the dollar or an unexpected rise in West German interest rates could halt the rally, and both developments are thought unlikely, they said.

Latest figures from the Frankfurt bourse, the biggest of West Germany's eight stock markets, put trading volume in the first six months of this year 67 percent higher than in the same 1984 period. Volkswagen, West Germany's biggest auto maker, yesterday reported profits of $92 million for the first six months of 1985, surpassing earnings for the whole of 1984.

It said sales were up sharply because of strong foreign demand.

VW Chairman Carl Hahn told the company's annual meeting in West Berlin that worldwide after-tax profits of around $92 million in the first half of 1985 compared with $75 million in all of 1984.

The strong first-half profit compared with a net loss of $53 million in the first half of 1984. VW blamed that on labor disputes at suppliers that shut down VW production for a month in early summer.

Hahn said worldwide sales rose 20 per cent from last year's first half, to almost $8.9 billion, with higher vehicle sales in all foreign markets except South Africa and Brazil.