Dortmund's shares were up more than 11 percent on the Frankfurt stock exchange early Monday before settling back to a still-hefty 8 percent rise in the afternoon.
The shares were trading at ¤3.02 ($4.15) and are now up 157 percent over the past year.
Dortmund, the only Bundesliga club with a stock market listing, last won the title in 2002 but has emerged as this season's surprise runaway leader.
With 10 rounds remaining, Coach Juergen Klopp's young team has a 12-point lead over second-place Bayer Leverkusen. It is 16 points ahead of Bayern after Saturday's victory.