with steady jet emission (e.g., @2003MNRAS.345.1057M; ; @2012MNRAS.423..590G). The detection of compact core radio emission is required in order to locate a ULX in the Fundamental Plane, which can be achieved only by means of very long baseline interferometry (VLBI) radio observations. [@2011AN....332..379M] initiated a program with the European VLBI Network (EVN[^1]) aimed at detecting and studying the milliarcsecond-scale emission of ULXs. Such investigations have indicated that those ULXs with radio counterparts may be powered by IMBHs (e.g., @2011AN....332..379M; @2013MNRAS.436.1546Ma, [-@2013MNRAS.436.3128M]c). Here, we investigate one of these ULXs in NGC4088. NGC4088 is an asymmetric spiral galaxy ($D_\mathrm{L}$ = 13 Mpc, redshift = 0.002524; ) hosting a ULX (N4088–X1) offset $\sim$32 arcsec from the nucleus. N4088–X1 was first detected with the *ROSAT* satellite by [@2005ApJS..157...59L], who reported an X-ray luminosity $L_\mathrm{0.3-8.0 keV} \sim 6 \times 10^{39}$ erg s$^{-1}$. The ULX is located within the spiral arm of NGC4088, possibly within an HII region (e.g., @2005ApJS..157...59L; ). A cross-match of the VLA[^2] FIRST[^3] catalog with *ROSAT* ULX catalogs (e.g., @2005ApJS..157...59L) revealed a 1.4 GHz VLA radio counterpart for the ULX of 1.87 mJy, with an offset between the *ROSAT* and the radio position of 3.6 arcsec (). Later EVN observations at 1.6 