Walnut Financial Services Inc., a long-struggling Richmond finance company, merged last week with Tower Hill Securities Inc. of New York to become THCG Inc. and ended its Virginia corporate career as the week's top-performing stock.

Shares of the new company doubled after completion of the merger and an announcement that Greenwich Street Capital Partners, an investment fund backed by Citigroup Inc., would invest $5 million in the firm. The company is moving to New York, where it will become an Internet specialist.

Xybernaut Corp. of Fairfax won two patents and said it was in "advanced talks" with International Business Machines Corp. about developing Xybernaut's wearable computers. The IBM announcement, though lacking in details, helped to double the stock price to $4.15 7/8 Thursday as more than 11.3 million shares were traded. The stock closed the week at $3.50, with 4.4 million shares traded Friday.

Teligent Inc.'s stock jumped $19 after the company announced a $500 million investment by a group headed by Microsoft Corp. and the private investment firm Hicks Muse Tate & Furst Inc. Teligent will use the funds to expand construction of its "fixed wireless" phone and data networks, which use radio waves to bypass local phone companies. Analysts said the investment, while solving the funding problem for the costly venture, also puts the company in a partnership with one of the nation's best-known high-tech companies.

The turnaround of LCC International Inc., which designs and builds wireless communications systems, continued to buoy the company's stock, which rose almost $5 to its highest level since last spring.

Broad gains by telecommunications and Internet-related stocks produced a 2 percent increase in The Washington Post-Bloomberg regional stock index.

The week's most significant losers were Lockheed Martin Corp. and its bride-to-be, Comsat Corp., as Lockheed Martin's long-overdue restructuring and management shake-up continued to scare off investors. Its stock fell along with that of Comast, which Lockheed Martin plans to acquire in a stock swap.