While many Americans may be moving in with relatives as a result of the housing crisis, the 38 Vanguard exchange-traded funds are set to begin rooming, listing and trading together, due to the acquisition of the American Stock Exchange by NYSE Arca.

The consolidation of all Vanguard ETF trading on NYSE Arca will commence this Friday morning.

There are already four Vanguard ETFs—Vanguard Mega Cap 300 ETF, Vanguard Mega Cap 300 Growth ETF, Vanguard Mega Cap 300 Value ETF and Vanguard Total World Stock ETF—trading on the NYSE Arca.

There have been many recent "housekeeping" moves in the ETF market as a result of the acquisition of AMEX by NYSE Arca. In at least one respect, the move of the AMEX-listed ETFs to NYSE Arca represents an important historical footnote for the ETF business.

AMEX was the original exchange home to the ETF market in its early days, at a time when many investors did not even know what a SPDR was and well before ideas like actively managed ETFs and hedge fund replication ETFs were even ideas in the product pipeline.

AMEX had seen its market share of ETF trading slip away in recent years as the bigger exchanges came to see the potential of the ETF business. ETF trading now represents 31% of all U.S. equities trading. (See related story.)

The dwindling of its share of the growing ETF market was one of the issues AMEX confronted in the days leading up to its decision to be acquired.

Vanguard has $51 billion in ETF assets, and its ETF family grew 25% in the year ended August 2008. Most notably, its Total Stock Market Fund, aided by rising assets of its ETF share class, recently passed its S&P 500 Index Fund as Vanguard's largest offering (see IU.com story).