production levels, commodity prices, royalty rates, costs and expenses, and deductions. Business Business income trusts are individual companies that have converted some or all of their stock equity into an income trust capital structure for tax reasons. Business income trusts are used in many sectors, such as manufacturing, food distribution, and power generation and distribution. They are not investment trusts in the classic sense, since they represent a single company's assets and not a pool of investments. Among business trusts, utility trusts that invest in or operate public utilities such as electricity distribution or telecommunications are sometimes put in a separate category as they are inherently less growth-focused. In the US, the business trust structure typically takes the form of publicly traded partnerships (PTPs) or master limited partnerships (MLPs), essentially limited partnerships (LPs) with units that trade on public securities exchanges. Those were very popular in the mid-1980s but are rare today. Revised IRS tax treatment of MLPs made the structure inefficient and infeasible, in light of the special tax that is levied on MLP owners who hold them in tax-deferred or exempt accounts such as 401(k)s, IRAs, and Roth IRAs. A more recent alternative called income depositary shares (IDS) has also failed to attract investor attention due to the trust activity being focused on the Canadian market. By country The tax advantages offered to trusts in certain jurisdictions have fueled investor interest in this type of investment vehicle. Australia Resource-rich Australia has had royalty trusts (and REITs) for a long time but in the early 1980s, a wider range of firms sought the same tax benefits and started converting into income trusts. Yield-hungry investors jumped on the bandwagon and rewarded the trusts with higher valuations. When Queensland Coal converted to a trust in 1984, its stock price tripled overnight. The Australian government, citing ever-increasing (but unquantified) losses of tax revenues, clamped down in 1985. All trusts except REITs and royalty trusts were given 3 years to find an exit strategy: to either keep the current structure at higher tax rates, or convert (back) to a public company. As unit prices started to collapse, the majority dropped the trust structure. It is notable, however, that the legal trust structure and the public trust structure persists in Australia to this day. As of December 2006, the Australian government was revisiting the income trust issue to consider whether further legislation was needed