Vanguard, Fidelity and Putnam all have open-end convertible mutual funds, and there are many closed-end funds, including some trading at discounts to their net asset values.

先锋，富达和Putnam Investments都有可转换开放式共同基金的，同时也有许多封闭式基金，包括一些基金在其净资产值以下。

youdao

Open-end mutual funds trade directly with investors, creating and destroying shares as needed to account for investments and withdrawals.

FORBES: Magazine Article

Unlike open-end mutual funds that are bought and sold at Net Asset Value (NAV), ETFs are traded throughout the day at whatever price clears the market.

FORBES: Are Commission-Free ETFs Really Cheaper?

My policy on bond investing is to only use open-end no load Institutional class mutual funds to invest in bonds.

FORBES: A Haven From A Eurozone Crash: Investment Grade Bonds