X0306 4 2013-03-21 0 0000827230 MICROFINANCIAL INC MFI 0001044321 MARXE AUSTIN W & GREENHOUSE DAVID M C/O SPECIAL SITUATIONS FUNDS 527 MADISON AVENUE, SUITE 2600 NEW YORK NY 10022 0 0 1 0 Common Stock 2013-03-21 4 S 0 2000 8.55 D 1540372 I By Limited Partnerships Common Stock 2013-03-21 4 S 0 15716 8.5682 D 1524656 I By Limited Partnerships Common Stock 2013-03-22 4 S 0 11275 8.631 D 1513381 I By Limited Partnerships Common Stock 2013-03-25 4 S 0 6871 8.6861 D 1506510 I By Limited Partnerships This is a weighted average price. This is a joint filing by Austin W. Marxe (Marxe) and David M. Greenhouse (Greenhouse). They share voting and investment control over all securities owned by Special Situations Fund III QP, L.P. (QP) and Special Situations Cayman Fund, L.P. (Cayman), respectively. 1,223,066 shares of Common Stock are held by QP and 283,444 shares of Common Stock are held by Cayman. The interest of Marxe and Greenhouse in the shares of Common Stock owned by QP and Cayman is limited to the extent of his pecuniary interest. Austin W. Marxe 2013-03-26 David M. Greenhouse 2013-03-26