A campaign finance package the Legislature advanced Wednesday afternoon would double the state’s limits on contributions to political candidates. The change would allow candidates to accept $1,000 checks from donors, rather than the $500 they’re currently limited to. The increase appears to be driven much more by the increasing costs of waging competitive campaigns, than by any great desire by Massachusetts residents to write larger checks to politicians.

The contribution limit changes were tucked into a larger overhaul of the state’s campaign finance regulations. Much of the package centered around beefing up disclosure regulations surrounding super PACs. The PACs, which were enabled by a 2010 Supreme Court decision, may raise and spend unlimited sums of money from individuals, corporations, and labor unions, as long as they’re not coordinating directly with political candidates.  State Sen. James Eldridge has been championing robust super PAC disclosures since the 2010 Supreme Court decision; a version of his PAC disclosure bill passed the Senate two years ago, but died in the House.

Super PACs have quickly risen to dominate high-profile state and local races, but even though they’re able to raise and spend money far more quickly than individual candidates, they only report their donors infrequently. The PACs poured millions into Boston’s mayoral race last year, but only disclosed their donors after the ballots had been counted in November. A number of PACs – some affiliated with traditional interest groups like labor unions, others explicitly linked to individual candidates – are now circling the governor’s race. “The governor’s race is a very high-profile race,” Eldridge says, “and I expect the money to come in fairly soon.”

CommonWealth reported in March that the PAC disclosure overhaul would likely also address contribution limits for donations made inside the traditional campaign finance system. As a practical matter, there’s not much difference between a $500 contribution ceiling, and one set at $1,000, when outside groups have the ability to raise and spend money far more quickly, and in greater amounts.

The vast majority of political fundraising in Massachusetts involves small sums of money. According to data from the state Office of Campaign and Political Finance, Massachusetts politicians have raised roughly $58.7 million, in 230,000 transactions, over the past 18 months. Seventy-nine percent of these transactions have involved contributions of $250 or less; contributions of $100 or less represent the majority of itemized contributions in the state campaign finance database since last January.

This incredible volume of small campaign contributions doesn’t equate to overwhelming sums of money, though. Despite representing nearly 80 percent of all the donations, contributions of $250 or less account for less than one-third of all the money ($18.7 million, out of a $58.7 million total) Massachusetts politicians and political committees have raised since last January.

Checks that hit the $500 contribution limit are relatively scarce. Less than one out of every five campaign contributions logged over the last 18 months have been for the $500 maximum. These maximum contributions go a lot further than small donations, though: Maximum donations make up less than 20 percent of the all recent Massachusetts campaign contributions, but account for 35 percent of the money in the system.

The amount of money changing hands at the $500 contribution limit hasn’t changed much over the last several years. CommonWealth compared the past 18 months of campaign finance activity to the similar time period eight years ago — the last time Massachusetts was in the run-up to an open gubernatorial election. The amount of money moving through the campaign system hasn’t changed much since the 2005-2006 election season, and the number of checks being written at the $500 contribution limit hasn’t moved all that much, either.

With $500 maximum contributions representing a minority of all the campaign finance activity in Massachusetts, and the volume of maximum contributions ticking up only incrementally, there doesn’t seem to be any great demand for higher contribution limits from political donors. Instead, it appears that the demand is coming from the politicians who set the contribution limits.

Massachusetts politicians have raised slightly less money over the past 18 months (a 3 percent dip) than they did in the same 18-month period eight years ago. But even though there’s less money flowing into the system, there’s more flowing out. Despite raising somewhat less money over the past 18 months, Massachusetts politicians have spent 9 percent more than they did eight years ago.

Even with a $1,000 individual contribution limit, Massachusetts would still have some of the tightest campaign finance regimes in the country. According to data from the National Conference of State Legislatures, just two states besides Massachusetts — Montana and Alaska — currently limit individual campaign contributions to statewide candidates to less than $1,000 per year. Another six states, including Rhode Island, New Hampshire and Vermont, set their annual contribution limits at $1,000.

A dozen states, including Texas, Indiana, Pennsylvania and Oregon, place no limits on individual contributions to candidates.