The brokerage industry, already in upheaval, got another jolt Tuesday after Citigroup (C) announced that it will spin off its Smith Barney brokerage unit and cede control of the venture to Morgan Stanley. The move would come on the heels of another recent seismic shift: Merrill Lynch officially being swallowed by Bank of America (BAC), creating the largest brokerage business.

Both moves leave investors with yet another reason to watch their money, and their brokers, like hawks. Here are three things to do if your broker gets spun off or sold.

1. Be vigilant--but don t panic.

Sudden mergers can scare investors into rash decisions, but panic selling often only leads to locked-in losses and unnecessary taxes and fees. Whether your brokerage gets bought or goes under, you--not your firm--still own the shares of stocks, bonds, mutual funds and cash in your account.

In the unlikely event that investments go missing, the Securities Investor Protection Corporation (SIPC) guarantees each customer s brokerage assets up to $500,000 in securities and $100,000 in cash. Still, investors should scrutinize their new brokerage s statement to make sure all investments correctly transferred over from the old firm.

2. Reassess your individual broker.

With more than 6,000 brokers likely to switch firms this year, a merger may lead your old broker to jump ship or your new firm to assign you a new broker. Investors in this situation should check the new broker s record at www.FINRA.org . Be sure the new broker matches your style and risk tolerance.

If you don t like the fit, ask your branch manager to reassign you to someone better. Too often, clients in a new broker relationship forget to ask tough questions and feel inferior, says securities lawyer Bryan Forman.

3. Drive a hard bargain.

Brokerages acquiring other firms are typically eager to keep existing clients, giving clients an unusual amount of leverage to negotiate. Compare the perks of the new firm (including access to no-load funds, higher interest rates on cash balances, free trades, lower commissions and fees) to the old one--and ask for more.

If a new broker suggests changing products or restructuring your portfolio, check the tax consequences and fees and that the changes benefit you. It s also a good time to make sure your old broker matched your portfolio to your current goals and needs, says George Feiger, CEO of Contango Capital Advisors.