Answer: acquiring a dominant position in a derivative to exploit the price of a related underlying.

## Explanation Transaction-based manipulation involves actions that directly affect market prices through trading activities rather than through information dissemination. **Option A is correct** because acquiring a dominant position in a derivative to exploit the price of a related underlying is a classic example of transaction-based manipulation. This involves using trading activities to artificially influence prices, which violates market integrity standards. **Option B is incorrect** because taking an aggressive investment position with intent to exploit market inefficiencies is generally considered legitimate trading activity, not manipulation. Market participants are allowed to take positions based on their analysis of market inefficiencies. **Option C is incorrect** because issuing overly optimistic projections to induce trading is an example of information-based manipulation, not transaction-based manipulation. This involves disseminating false or misleading information rather than directly manipulating prices through trading activities. **Key distinction**: - **Transaction-based manipulation**: Involves trading activities that artificially affect prices (e.g., wash trades, painting the tape, cornering markets) - **Information-based manipulation**: Involves disseminating false or misleading information to affect prices Under CFA Institute Standards of Professional Conduct, both types of manipulation are prohibited, but they represent different methods of market manipulation.

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