The money management arm of National Penn Bancshares Inc. has scooped up Resources for Retirement Inc.

National Penn, Boyertown, Pa., is a midsize bank with about $5 billion in assets.

Resources for Retirement, Newtown, Pa., is a retirement plan investment advisory firm.

Trisha Brambley, the founder and president of Resources for Retirement, helped create the modern 401(k) plan, according to WFG Capital Advisors L.P., Harrisburg, Pa., the investment bank that represented Resources for Retirement in the transaction.

National Penn hopes to use the acquisition to increase its ability to sell 401(k) plans to larger employers, WFG says.

Resources for Retirement will keep its name and executives while operating as a division of National Penn’s National Penn Capital Advisors Inc. unit, WFG says.