IT’S DANGEROUS TO LEAVE millions of dollars lying around these days on Beacon Hill. Someone is likely to snatch the money.

The state’s Horse Race Development Fund is a case in point.  Set up to sweeten the purses of horse races, the fund draws its revenue from a tax on casino gambling. Harness races in Plainville are receiving money from the fund, but a good chunk of the revenue set aside for thoroughbred racing is going unused. The state’s lone thoroughbred track, Suffolk Downs, was recently sold and is planning just six race days this year. Next year, no one knows.

Officials at the Massachusetts Gaming Commission say the Horse Race Development Fund currently has a balance of about $13 million.

With so much money sitting idle, there is no shortage of suggestions on what to do with the cash. The New England Horsemen’s Benevolent and Protective Association wants to tap the fund to finance the study and possible construction of a $150 million horse park in central Massachusetts.  Rep. Brad Jones, the House Republican leader, has filed a bill to use $10 million a year from the Horse Race Development Fund to replenish the state’s Community Preservation Trust Fund.

And the Senate Ways and Means Committee on Tuesday filed a fiscal 2018 budget proposal that calls for using $15 million from the fund to support two cash-strapped state agencies – the Department of Agriculture and the Department of Conservation and Recreation.

Sen. Patricia Jehlen, a Democrat from Somerville, said the money from the Race Horse Development Fund will help raise the funding level of the Department of Conservation and Recreation $3 million above what the governor proposed in his budget. But Jehlen noted DCR’s funding will still be less than what it received this year; she said DCR is just one example of many underfunded programs in the state budget.

“This is a budget that is inadequate to meet our needs and obligations,” she said after the Senate Ways and Means Committee approved the budget. “It shows that we have a revenue problem, not a spending problem.”

Expect a fight over who should get the money in the Horse Race Development Fund. The New England Horsemen’s Benevolent and Protective Association, for example, makes the case that the money in the fund was intended to promote horse racing. What better way to promote horse racing than to promote a horse park with a track, officials said.

“When we look at that money in the Horse Race Development Fund, we see 1,000 jobs and the preservation of open space,” said Paul Umbrello, executive director of the horsemen’s association. “We will fight the transfer.”

The $15 million from the Horse Race Development Fund is one part of a $400 million package of new revenue measures in the Senate budget proposal. Here’s a rundown of some of the major initiatives.

Health care assessment – The Senate budget plan calls for a $180 million assessment on employers to offset the rising cost of Medicaid. The plan gives the governor two options: a direct assessment on employers with 25 or more employees (the governor’s proposal covered businesses with 10 or more employees) or a hike in the Employee Medical Assistance Contribution from its current level of $51 per employee.

Sales tax initiatives – One proposal would raise $125 million by speeding up sales tax payments by third party credit card processors and the other would raise $30 million by collecting sales tax on more internet purchases by Massachusetts residents.

Short-term rentals – Called the Airbnb tax, the $18 million initiative applies the state’s room occupancy tax to short-term rentals. The Senate initiative applies the tax to all short-term rentals, while the governor wanted it to apply to only those who rent rooms more than 150 days a year.

Room resellers – Some websites purchase room nights in bulk and then sell them individually to consumers. The websites pay tax on the initial bulk purchase, but don’t pay tax on the marked-up price of the rooms they resell to consumers. The Senate initiative would tax the markup, generating $7 million.

Earned Income Tax Credit – The Senate provision would bar out-of-state residents from collecting the earned income tax credit, saving the state $10 million.