Asset management firms implement investment strategies to achieve objectives concurrent with the funds they offer. Their clients invest in funds, for which the fund managers provide a professionally managed portfolio of securities. The funds offered by such firms provide diversification to portfolios, which can have cost benefits since investors do not have to purchase multiple securities in their portfolios. However, asset management firms charge fees to invest in their funds and have minimum investment requirements.

Investors looking for funds that can be purchased on a share-by-share basis, rather than investing a specified minimum dollar value, are able to invest in exchange-traded funds (ETFs), which are offered by some asset management firms, but working with a financial advisor and choosing one of the top asset management firms can foster long-term relationships, and can even keep down costs. 

The Vanguard Group

The Vanguard Group is one of the most well-known investment management companies and caters to over 20 million clients in 170 countries. Vanguard was founded by John C. Bogle on May 1, 1975, in Valley Forge, Pennsylvania. Bogle was Wellington Management Company's chairman and decided to start Vanguard as a division of Wellington. Since 1975, Vanguard has grown its total assets to $5.1 trillion as of October 2018. It offers 388 funds, 180 of which are U.S. funds. Vanguard's popular funds include the 500 Index, Total Stock Market and FTSE All World Funds.

Pacific Investment Management Company, LLC

Pacific Investment Management Company LLC (PIMCO) is a global asset management firm that was co-founded in 1971 in Newport Beach, California, by the bond king Bill Gross. Since the inception of PIMCO, the firm has grown its assets under management (AUM) to $1.77 trillion as of October 2018. The firm houses over 775 investment professionals, who have an average investment experience of 14 years. PIMCO offers over 100 mutual funds, which range from fixed-income, equity and commodity-focused funds. PIMCO is known as one of, if not the, leader in the fixed income sector of investing. 

BlackRock, Inc.

BlackRock Inc. (BLK) was founded in 1988 as an asset management firm with $1 billion in assets under management as a division of the BlackRock Group. The firm assumed the name BlackRock in 1992, and by the end of year, had $17 billion in assets under management. As of October 2018, the fund has $6.32 trillion in assets under management, which makes it the world's largest investment management firm. It has over 12,000 employees in over 70 offices in 30 countries. As of October 2018, BlackRock's ETF division, iShares, had $1.6 trillion in AUM globally which amounted to 27% of the group's total AUM, offering 343 ETFs and 598 mutual funds.

Fidelity Investments

Fidelity Management & Research Company was founded in 1946 by Edward C. Johnson II. As of October 2018, Fidelity has 24 million customers with $6.9 trillion in combined assets. Additionally, it has $2.1 trillion in global AUM. Fidelity offers 386 mutual funds, which include domestic equity, foreign equity, sector-specific, fixed-income, index, money market and asset allocation funds. It offers many notable large funds, most of which are considered the bedrock of an individuals investment portfolio. 

Invesco Ltd.

Invesco Ltd. (IVZ) is an asset management firm whose investment management services date back to the 1940s. It announced a $987.8 billion preliminary month-end AUM in August 2018. The fund offers over 100 mutual funds. The firm offers over 100 ETFs through its Invesco PowerShares Capital Management LLC division. In 2017, the company saw some downturn in AUM, which it attributed to a few different factors. Despite the downturn in their stock price as a result, Invesco remains one of the top asset management firms in the world.