WASHINGTON — With Wall Street engulfed in crisis, the Securities and Exchange Commission is planning measures to rein in aggressive forms of short-selling that were blamed in part for the demise of Lehman Brothers and which some fear could be turned against other vulnerable companies.

During emergency meetings between federal officials and investment bank executives over the weekend, SEC Chairman Christopher Cox indicated to the bankers that the agency plans in a few days to impose new permanent protections against abusive "naked" short-selling, a person familiar with the matter said yesterday.

Unlike the SEC's temporary emergency ban this summer covering naked short-selling in 19 stocks, the new measures would apply to trading in the broader market.