Or search: steal, buying, bargain, buyback, leverage, subscribe, purchasing, redemption, repurchase, acquisition, mercantilism, commercialism
3 Syllables: SUU
burgesses, earnestness, furnaces, hermitage, nervousness, purposeless, purposes, services, surfaces, surpluses, worthlessness
4 Syllables: USUU
affirmative, alternative, conservative, disturbances, divergences, encourages, interpretive, observances, preservative, superlative

Found 21 words across 2 groupings. Skipped 2 excess words of a similar stem.