Client fund investment restrictions: portfolio managers must invest only per client agreement and segregate holdings. Regulation 16 requires portfolio managers to invest and manage client funds only per the written client agreement, treats renewals as fresh placements, permits client withdrawals before maturity in specified events, and limits investments to prescribed instruments while prohibiting leveraging in derivatives and deployment in bill discounting, badla financing or lending. Managers must avoid speculative non delivery transactions (except derivatives), effect client transactions separately or allocate aggregated trades pro rata at weighted average prices, transact at prevailing market prices, segregate client assets from their own, refrain from holding portfolio securities in their own name subject to transitional exceptions, and may engage in securities lending only with written client authorization.