The Bricklayers and Trowel Trades International Pension fund is a multiemployer (or Taft-Hartley) pension fund operated by and on behalf of the members of the International Union of Bricklayers and Allied Craftworkers, a labor union that is affiliated with the AFL-CIO labor union federation. The Fund boasts over 10,000 contributing employers and over 100,000 plan participants. As with other union pension funds, participation is closed to industry workers who work in non-union positions. 
The Bricklayers and Trowel Trades International Pension Fund was founded in 1973 by the International Union of Bricklayers and Allied Craftworkers and various other companies and employers within the bricklayer and masonry industry. The plan is financed by employer contributions that are agreed upon as part of collective bargaining agreements brokered between employer companies and the union. The fund is made up of a board equally represented by union members and employer companies, and is exempt from federal income taxes under section 501(a) of the Internal Revenue Code. 
Participation in the fund is open solely to employees operating under a Bricklayers collective bargaining agreement and specifically excludes any individuals working as sole proprietors, self-employed, or partnerships. Employees are eligible for one of four types of pensions: early retirement, regular pension, disability, and deferred vested pensions. 
The pension fund offers both past service and future service credits, meaning that participants are able to earn years of service credit for previous years of service during which the individual worked in union-covered employment, participants also earn one year of service for every year they work at least 1,500 hours in a union job after they begin contributions to the pension fund. 
The Bricklayers and Trowel Trades International Pension Fund has drawn criticism and lawsuits over its strict policy of not allowing non-union masons and bricklayers to participate in the plan. In most cases participating in non-union work can prohibit one from gaining access to the pension fund. 
In one case, the pension fund board enforced a rule that that a man had participated in at least one hour of non-union employment over his career. This let the pension fund to cancel his access to an early retirement pension and delay his retirement by 13 years. 
The Bricklayers and Trowel Trades International Pension Fund, like most labor union-affiliated groups and AFL-CIO affiliates is engaged in left-leaning activism. Specifically, given that the fund manages a large amount of assets the fund is known for shareholder activism, in which the fund files shareholder resolutions in an attempt to move the corporate governance of many large corporations further to the left on both public policy and labor issues. A 2018 report on annual corporate governance found that the fund had submitted at least three shareholder resolutions to Charter Communications and Hasbro respectively that dealt with requiring an independent board chairman and clawbacks of executive compensation incentives.