Underfinance rhymes with:
finance, nance, refinance, advance, alamance, anse, askance, chance, crance, dance, duran's, enhance, expanse, finance, france, glance, hance, lafrance, lance, mance, mccance, nance, perchance, pomerance, pomeranz, prance, rance, refinance, romance, schanz, schranz, stance, trance, vance
Underfinance sounds like:
underpaying, underpinning, underpinnings