Trenkler [13] described an iteration estimator. This estimator is defined as follows: for 0<γ<1/λi max β^m,γ=γi=0∑m(1−γX′X)iX′y where λi are eigenvalues of X'X. In this paper a new estimator (generalized inverse estimator) is introduced based on the results of Tewarson [11]. A sufficient condition for the difference of mean square error matrices of least squares estimator and generalized inverse estimator to be positive definite (p.d.) is derived.Trenkler [13] described an iteration estimator. This estimator is defined as follows: for 0<γ<1/λi max β^m,γ=γi=0∑m(1−γX′X)iX′y where λi are eigenvalues of X'X. In this paper a new estimator (generalized inverse estimator) is introduced based on the results of Tewarson [11]. A sufficient condition for the difference of mean square error matrices of least squares estimator and generalized inverse estimator to be positive definite (p.d.) is derived