This is not investment advice. The information provided is for educational and informational purposes only and does not constitute a recommendation to buy or sell any financial product.
Granting a power of attorney (POA) for a stock trading account is a delegation of authority, and the delegation carries real risks. The third party can mismanage the account, over-trade, place the account in a conflict of interest, or simply make bad decisions that the account holder is responsible for. The mitigations are also real: a well-drafted POA, a clear agreement with the third party, and a structured oversight framework can reduce the risks to an acceptable level. The trade-off is worth understanding before the POA is signed.
The mismanagement risk
The first risk is mismanagement. A third party who trades on the account holder's behalf can make decisions that the account holder would not have made. The decisions can be poorly timed, poorly sized, or based on a view that the account holder does not share. The result is a loss on the account that the account holder is responsible for, because the account holder is the legal owner of the assets.
The mismanagement risk is most acute when the third party is a friend or family member with no professional experience. The third party can be well-intentioned, but the third party is not a professional, and the third party's decisions are not constrained by the same rules that constrain a professional. The account holder who delegates to a friend is delegating to someone who is not bound by the same fiduciary duty as a professional.
The mitigation is to choose a third party with a track record, a clear agreement, and a structured oversight framework. A professional investment manager is bound by a fiduciary duty, the agreement defines the strategy and the risk limits, and the oversight framework includes regular reporting and a review of the manager's performance.
The over-trading risk
The second risk is over-trading. A third party who is paid a commission on each trade has an incentive to trade frequently, and the over-trading can erode the account's returns through commissions and spreads. The over-trading is a particular problem when the third party is paid by the trade, not by the assets under management.
The mitigation is to pay the third party by the assets under management, not by the trade. A fee of 1% of the assets per year aligns the third party's incentive with the account holder's incentive, and the third party is rewarded for growing the account, not for trading the account. The fee is a real cost, but the cost is lower than the cost of over-trading on a commission basis.
A second mitigation is to set a maximum trade frequency in the agreement. The third party is allowed to place, say, 20 trades per month, and the cap prevents the over-trading. The cap is not a perfect protection, because the third party can still trade frequently within the cap, but the cap is a real constraint.
The conflict of interest risk
The third risk is the conflict of interest. A third party who is also a broker, or who is affiliated with a broker, can have an incentive to direct the account's trades to the affiliated broker. The directed trades may not be the best execution for the account, and the conflict is a real cost on the account.
The mitigation is to require the third party to disclose all affiliations, and to require the third party to obtain best execution for the account. The disclosure is a legal requirement in most jurisdictions, and the best execution is a regulatory requirement. The account holder can also require the third party to use a specific broker, and the account holder can monitor the trades for signs of directed trading.
A second mitigation is to use a third party who is independent of any broker. An independent investment manager is paid by the account holder, and the manager has no incentive to direct trades. The independent manager may charge a higher fee, but the fee is the cost of removing the conflict.
The loss of control risk
The fourth risk is the loss of control. A POA gives the third party the authority to trade, and the account holder has no real-time visibility into the trades. The account holder receives a statement at the end of the month, and the statement shows the trades, but the account holder does not see the trades as they happen. The loss of control is uncomfortable for an account holder who is used to trading the account directly.
The mitigation is to require the third party to provide real-time access to the account, and to require the third party to notify the account holder of any trade above a defined size. The notification is a real constraint, because the third party cannot place a large trade without the account holder's knowledge. The constraint is not a perfect protection, because the third party can still place a small trade without notification, but the constraint is a real limit.
A second mitigation is to use a trading-only POA, not a full POA. A trading-only POA authorises the third party to place trades, but the third party cannot withdraw funds or close the account. The account holder retains the right to fund and defund the account, and the third party's authority is limited to the trade execution. The trading-only POA is the narrowest delegation, and it is the safest.
The tax risk
The fifth risk is the tax risk. A third party who trades aggressively can produce a large tax bill for the account holder, even if the trades are profitable. The account holder is responsible for the tax, and the third party is not. The tax bill can be larger than the account holder expected, and the account holder is the one who has to pay it.
The mitigation is to agree on a tax-efficient strategy with the third party before the POA is granted. The strategy defines the holding period, the turnover, and the use of tax-advantaged accounts. The account holder's tax adviser can advise on the tax-efficient strategy, and the third party's compliance with the strategy can be monitored through the monthly statement.
How to manage the risks
The honest answer is to choose the right third party and the right type of POA. A general POA is appropriate for a spouse or a long-term adviser. A limited POA is appropriate for a discretionary manager. A trading-only POA is appropriate for a copy-trading follower. The broker's legal team can advise on the form of the POA, and the account holder's tax adviser can advise on the tax consequences. Our broker comparison lists the account types and the broker's POA policy, which together tell you what is on the table before you sign the document.