"It's obvious I will never be a candidate again for any elected political office," she told journalists.
Bachelet has been a towering figure on the Chilean political scene since first winning the presidency in 2005.
She left office in 2010 with an approval rating of 83 percent, then, barred from serving a second consecutive term, surged back to power in the December 2013 election, winning 62 percent of the vote and becoming the first president to serve more than one term since Chile's return to democracy in 1990.
Compagnon's company used the money to buy property that was then slated for urban rezoning, selling the land at a $5 million profit.
Also Read
Bachelet denies any prior knowledge of the loan, but the scandal has seriously dented her image as a reformer.
Under Chile's constitution, which bars consecutive presidential terms, Bachelet is not eligible for immediate reelection, but she could serve in Congress or other elected office.
"I'm worried by this climate of suspicion in the face of everything," she said.
Bachelet said earlier this month she has no plans to resign.