For banks in the mutual fund business, a new gold rush is about to  begin. 
Bankers are preparing to pump as much as $153 billion of common trust  fund assets into their mutual funds, the government has estimated, now that   President Clinton has pledged to sign a tax-free conversion measure into   law.     
  
The measure, part of minimum-wage legislation Mr. Clinton is expected to  sign this month, will let bankers transfer common trust assets into mutual   funds without triggering capital gains taxes for trust beneficiaries.   
That's good news for bankers who are still waiting to make a profit  managing mutual funds. Common trust assets are the last ready pool of money   available to push proprietary mutual funds toward a critical mass that   would generate meaningful management fees.     
  
"It's a very important event for the money management business in  banks," said Peter F. Mackie, executive vice president at Commerce Bank,   St. Louis. Commerce Bank has $700 million in six common trust funds that   could be added to the bank's $540 million-asset mutual fund complex, he   said.       
Even banks that already have sizable fund families could benefit from  simplified product lines, potential cost savings, and improved economies of   scale with an infusion of assets into mutual funds. Indeed, most banks with   both common trust funds and mutual fund families are expected to take   advantage of the tax-free conversion, several experts said.       
"Common trust funds have largely outlived their usefulness," said Eugene  F. Maloney, corporate counsel at Pittsburgh-based Federated Investors, a   champion of the conversion measure. "They're not as flexible as mutual   funds, and because of their relatively modest size, they're cost centers"   at many banks, he said.       
  
Already, some banks have used a recent regulatory ruling by the Internal  Revenue Service to make the transfer, in effect, by investing their common   funds in mutual funds. Under the new conversion law, banks that have taken   this route since Dec. 31 will be allowed to dissolve the common trusts they   had been required to keep on their books.       
Much as employee benefit plan assets helped many banks start their fund  families, tax-free conversions may spark a raft of new mutual funds with   investment objectives that match the common funds they supplant.   
"We've got three approved mutual funds that are approved and on the  shelf just waiting for assets," said Timothy Leach, president of Qualivest   Capital Management, U.S. Bancorp's $2 billion-asset mutual fund unit. The   three are a large-cap growth stock fund, a national municipal bond fund,   and an income-equity stock fund.       
The Portland, Ore.-based banking company is likely to shift nearly $300  million of common trust assets into mutual funds this year, boosting   proprietary fund assets by at least 15%, Mr. Leach said.   
  
Besides cost advantages for banks that have mutual funds, the conversion  measure will enable trust departments to lean more heavily on mutual funds   as their investment vehicle of choice. That promises to simplify many   banks' product lines and help them appeal to consumers who increasingly   prefer mutual funds as the way to invest, several executives said.       
"There are clients who perceive that being in a mutual fund is somehow a  step up from being in a trust fund managed world ...," Mr. Leach said. 
Banc One Corp., Columbus, Ohio, has already configured its common trust  funds to mirror its family of 26 mutual funds, said Mark A. Dillon,   president of One Group Services Co., the administrator and distributor of   Banc One's proprietary funds.     
After completing a legal and regulatory review, he expects Banc One to  move $2.5 billion of common fund assets into the bank's $13.7 billion-asset   fund family within four months.   
"Unless there are some compelling client reasons" not to, "which we  don't perceive there are, Banc One would close the common trust funds," Mr.   Dillon said.   
But not everyone is hurrying to abandon their common trust funds for  mutual funds. 
"There's an opportunity to add bulk to existing mutual funds, but we  wouldn't do it if there's no real customer benefit,"said Richard H. Jones,   chief asset management executive at Barnett Banks Inc., Jacksonville, Fla.   
Barnett, which has $4 billion of proprietary mutual fund assets, is  analyzing whether a conversion makes sense, he said, adding, "We're not   motivated by a need to get scale in our complex."