The federal jurors found Stanford guilty on 13 of 14 counts he faced. They found Stanford not guilty on one count of wire fraud.
The 61-year-old Stanford looked down when the verdict was read.
He faces up to 20 years in prison for the most serious charges but could be imprisoned for much longer if a judge orders his sentences be served consecutively.
Prosecutors say Stanford orchestrated a 20-year scheme that took billions through the sale of certificates of deposit from his Caribbean bank.
Stanford's attorneys blamed his ex-chief financial officer.