When K is R, C or H, let
UK(n) denote the group of n × n orthogonal, unitary, or symplectic matrices,
respectively. If G is a closed connected subgroup of UK(n) of maximal rank, then it is
conjugate to a subgroup of the form UK(n1) × UK(n2) ×⋯× UK(nk). A
simple condition on the integers ni is shown to be necessary for UK(n)∕G to
have the fixed point property (that every self map has a fixed point). It is
conjectured that this condition is also sufficient, and a proof is given for some
cases.