Research by CBC News has revealed that prominent developers were among the top donors to the Progressive Conservative Party of Ontario in 2016, helping it amass more money than any political party in this province has ever collected in a year.

The Ontario PC fundraising machine kicked into high gear in 2016, collecting $12.9 million, more than double the Ontario Liberal Party's total. This happened as reforms were being introduced to ban corporations and unions from donating to the province's political parties, and as Liberal Premier Kathleen Wynne's approval ratings sunk to record lows.

Data on who donated how much to each political party is publicly available from Elections Ontario, but the donations are not sorted in a way that reveals who gave the most.

CBC News crunched the numbers to discover that the top donor to the PCs in 2016 was Orlando Corporation, which bills itself as "Canada's largest privately-owned industrial real estate developer and landlord."

Donations totalling $159,600 came from Orlando Corp. and its subsidiaries, including Orlando Development Inc., Orlando Construction Inc., Quarre Properties Inc. and Heartland (Seven) Ltd.

Here's the list of the top donors to the Ontario PCs in 2016:

Orlando Corp. $159,600

Medipac $100,415

LIUNA $74,070

Canerector Inc & Hawkins Family $69,825

Silver Hotel Group $59,185

Insurance Bureau of Canada $43,460

Mattamy Homes Ltd. $42,430

Merit Open Shop Contractors Assoc. of Ontario $41,290

Federation of Rental Housing Providers of Ontario $38,100

Colonial House Capital Ltd. $33,500

Valley Blades Ltd $32,500

Interior Systems Contractors Assoc. of Ontario $31,775

The leader of the Ontario Progressive Conservative Party, Patrick Brown. (Mike Crawley/CBC)

12 other companies each donated $29,925 to the PCs in 2016: Canadian Motorsport Ventures Ltd.

Carallas Holdings Ltd.

Carfin Holdings Inc.

Dixie South Gateway Inc.

Elkland Capital Inc.

Nevada Capital Corp.

NMA Leslie Newmarket Inc

NMV Bogartown Newmarket Inc

Orfid Investment Corp.

Royalvit Estates

Triple Delta Holdings Inc.

Wind Mobile Corp.

During 2016, Ontario's Election Finances Act limited donors to giving $9,975 to a party each year. However, donors were also allowed to give $9,975 during each election period, including byelections. There were three separate byelection periods in 2016. Donors were also allowed to give a maximum of $1,330 to candidates during each byelection period.

Each subsidiary of a company was also legally allowed to give the maximum, as could directors or senior executives of a company. The $100,415 donated by the PCs' number two donor, Medipac, includes donations from Medipac Assistance Inc., Medipac International Communications Inc., and Medipac International Inc, all part of Medipac Travel Insurance, headquartered in Toronto. In addition to that amount, Medipac's CEO John Quigley personally donated $33,915 to the PCs.

The PCs' biggest union donor was the Labourers International Union of North America (LIUNA). Its $74,070 in donations included contributions from LIUNA Candian Tri-Funds, the LIUNA Provincial Council, and several LIUNA locals, each of which was legally entitled to give the maximum.

New laws that took effect Jan. 1 banned corporate and union donations and also drastically reduced the amount an individual donor can give each year. However, the three main parties and the Green Party of Ontario will each receive taxpayer-funded allowances starting this year.

Figures from Elections Ontario show the PCs vastly out-fundraised the governing Liberals and the third-place New Democrats in 2016:

Ontario PC Party: $12,924,953

Ontario Liberal Party: $6,309,082

Ontario NDP: $3,718,010

This was a switch from 2015, when the Liberals raised $9.2 million, double the PCs' haul for the year. The PC Party collected its funds from 9,945 separate donations.

The banner year wiped out the PCs pre-existing debt of $6 million, leaving the party with a surplus of $2.1 million. The other two parties both remain in debt: the Liberals at $2 million in the red, and the NDP $3.2 million.