Investment advisor deals, once a fragmented backwater of financial services, are surging as Wall Street eyes fees in a business with pricing power. Mergers and acquisitions involving wealth advisors and brokers reached a seven-year annual high in November, according to data compiled by Bloomberg. That was even before Charles Schwab Corp.’s blockbuster $26 billion agreement to purchase TD Ameritrade Holding Corp. Wall Street is flush with cash and companies from Goldman Sachs Group Inc. to private equity firms are investing in wealth managers for their stable revenue streams.