A new phenomenological model is proposed to describe the evolution of the Fermi surface (FS) in a wide range of dopings. It reproduces the key features of the cuprates in the underdoped phase above the superconducting temperature Tc. It is shown that the explicit accounting of strong electron correlation in the framework of the t−J model taken in complementary to the translational symmetry breaking induced by the charge density wave (CDW) gives rise to the Fermi surface reconstruction (FSR) into small electron pockets. While the strong Coulomb repulsion leads to an emergence of the arc-like Fermi surface in the pseudogap (PG) phase, the Bragg reflection on the boundaries of the reduced Brillouin zone (BZ) opens up a possibility to close the quasiparticle orbits. Direct calculation of the FS properties allows us to unveil the scenario of the experimentally observed transition to the CDW phase that sets in at the doping level δ ≈ 0.08 and is accompanied by a divergence of the carriers effective mass and the sign reversals of the Hall and Seebeck coefficients.Introduction. The discovery of quantum oscillations in the underdoped YBa 2 Cu 3 O 6+δ (YBCO) in a high magnetic field[1-3] revealed among other features a reconstruction of the Fermi surface into small pockets. Further measurements[4] also established that the area of the FS is proportional to the doping value δ instead of the 1 + δ as predicted by the conventional Fermi liquid (FL) theory. The sign changes of both Hall[5] and Seebeck[6] coefficients in the doping range of 0.08 < δ < 0.16 indicates that, at a low temperature, electron-like pockets emerge due to the translation symmetry breaking that takes place in the ground state of the non-superconducting phase. The subsequent detection of quantum oscillations in YBa 2 Cu 4 O 8 [7,8], HgBa 2 CuO 4+δ [9] and other compounds [10][11][12][13][14] confirms that such a FSR is a generic property of the underdoped cuprates.All those compounds reveal the presence of the CDW modulation right at the very doping level where the FSR has been detected. It was shown that, for YBCO, the incommensurate CDW modulation vectors lie in the CuO plane and they take the form Q x = 2π(Q, 0) and Q y = 2π(0, Q) with Q ≈ 0.31 [15][16][17][18]. This CDW ordering with a period varying from 3 to 5 lattice spacings has also been detected by scanning tunneling microscopy (STM) and x-ray diffraction (XRD) studies in underdoped cuprates [19][20][21][22][23][24][25][26][27][28]. Those experimental evidences strongly suggest that this charge ordering indeed is the leading cause for the observed FSR. Also, a number of experiments revealed a predominant d-wave form factor of the CDW ordering [29][30][31].The phenomenological calculations confirm that the electron-like pockets in the nodal regions can be obtained within the one band phenomenological tight-binding model by breaking translation symmetry by multiple-Q ordering [32]. Extending that model to incorporate a long-range charge order with the d-form factor [33] pro-