Counter position is hard to define in a large market, so take a market with two stocks A and B. You buy shares of A from counter-position-inc who moves that money into B (possibly buying the shares you just dumped).
Over a time period A goes up 5% B goes up 10%. You sell your shares in A (profitably) but under performed the average market returns by 2.5%. counter-position-inc sells its shares in B, over performing the market average by 2.5%.
Over a time period A goes up 5% B goes up 10%. You sell your shares in A (profitably) but under performed the average market returns by 2.5%. counter-position-inc sells its shares in B, over performing the market average by 2.5%.