diff --git a/include/boost/math/tools/toms748_solve.hpp b/include/boost/math/tools/toms748_solve.hpp
index 0e4f5a8bd..dca6bf021 100644
--- a/include/boost/math/tools/toms748_solve.hpp
+++ b/include/boost/math/tools/toms748_solve.hpp
@@ -112,7 +112,7 @@ void bracket(F f, T& a, T& b, T c, T& fa, T& fb, T& d, T& fd)
    }
    else if(c >= b - fabs(b) * tol)
    {
-      c = b - fabs(a) * tol;
+      c = b - fabs(b) * tol;
    }
    //
    // OK, lets invoke f(c):