We report a study of the eclipse timing variation (ETV) of short period (P1=<6d) eclipsing binaries (EBs) monitored during the photometric survey optical gravitational lensing experiment-IV. From the 425193 EBs, we selected approximately 80000 binaries that we found suitable for further examination. Among them, we identified 992 potential hierarchical triple (or multiple) system candidates exhibiting light-travel time effect (LTTE). Besides, we obtained the orbital parameters of these systems and carried out statistical analyses on the properties of these candidates. We found that (i) there is a significant lack of triple systems where the outer period is less than 500d, (ii) the distribution of the outer eccentricities has a maximum around e_2_~0.3, and (iii) the outer mass ratio calculated from an estimated minimum mass of the third component is lower than q_2_~0.5 for the majority of the sample. We also present some systems that deserve special attention: (i) There are four candidates that show double periodic ETV, which we explain by the presence of a fourth companion; (ii) For two systems, the perturbations of the third component are also found to be significant therefore we give a combined dynamical and LTTE ETV solution; and (iii) For one system, the third component is found to be probably in the substellar mass domain.

Cone search capability for table J/MNRAS/485/2562/table1 (LTTE solutions for the 258 most certain hierarchical triple star candidates of the OGLE-IV sample)

Cone search capability for table J/MNRAS/485/2562/table2 (LTTE solutions for the remaining, less certain hierarchical triple star candidates of the OGLE-IV sample)

Cone search capability for table J/MNRAS/485/2562/table3 (Orbital elements from combined dynamical and LTTE solutions)

Cone search capability for table J/MNRAS/485/2562/table4 (Results of double LTTE solution fit)

Cone search capability for table J/MNRAS/485/2562/table5 (The seven systems where the third component has higher mass than the EB)