Of the total 199 small and medium enterprises (SMEs) listed this year so far, 22 had an issue size of less than Rs 10 crore, which the Securities and Exchange Board of India (Sebi) will no longer allow in the listed ecosystem after its recent consultation paper.The market regulator on Tuesday proposed an overhaul of the rules governing the initial public offerings (IPOs) of SMEs and corporate governance norms for listed SMEs, following concerns over 'systemic risk' seen in the ecosystem with instances of fund diversion and price manipulation.