With the MLB trade deadline approaching, texts are pinging between front-office executives, general managers are holding hushed phone calls, and amateur internet sleuths are breaking major stories. But swapping players isn’t just a deadline pastime these days. Whether it’s the result of rule changes, smarter front offices or the natural ebbs and flows of the market, the last few years have featured more trades than ever before, both before and after the deadline, making the deadline less relevant in relation to the rest of the year.

Regardless of your rooting interests, it’s always entertaining to watch the buyers and sellers jostling to make the best deadline deal. On a day-by-day basis, this part of the season has always been the busiest part of the baseball calendar for trades, and it shows few signs of slowing down.

However, the percentage of all trades taking place at the deadline has actually gone down in the past eight years, with teams trading up a storm throughout the entire year. Since 2009 (the first year for which Baseball Prospectus has transaction data), the total volume of trades across MLB has increased by an average of 14 percent every season. Deadline deals used to make up about quarter to a third of all trades; in the last four years they only represented roughly one-sixth of of all trades.

There isn’t an immediate or obvious reason why trades have spiked so dramatically. Rule changes — especially those included in a new collective bargaining agreement (CBA) — could have contributed. Before 2012, teams were eligible to receive a draft pick in return for a free agent who left the team, even if he was traded to that roster midseason. Under the new CBA, which went into effect in 2012, the value of those potential free agents dropped, since a team could no longer get draft-pick compensation for them. But the increase in trade volume appears to be a gradual rise, not the one-time bump we’d expect to see immediately after the CBA was adopted if the change in rules was responsible for the rise.

Likewise, we might expect the recent dramatic increase in front-office jobs (particularly in analytics) to help boost trade volume because all those new workers could increase a team’s ability to juggle multiple potential offers. (The older, smaller front offices likely would have been forced to focus on only one deal at a time.) But there’s also very little correlation between the number of analysts in a front office and the frequency of trades, so it seems like front-office expansion isn’t to blame.

Two more legitimate contributing factors, however, might be the second wild-card slot (instituted in 2012) and the newfound prevalence of tanking in MLB. The additional playoff spot encourages more teams to try to contend, which has sometimes resulted in an arms race of acquiring talent at the trade deadline. Last year’s American League East featured three teams (the Boston Red Sox, Toronto Blue Jays and Baltimore Orioles) buying pitching in July, presumably with the hope of vaulting into contention.

Tanking works in the opposite direction: When teams are forced to decide between the playoffs and rebuilding, they have more incentive to either trade their valuable players or gain additional strength. The White Sox were frozen in mediocrity for a long time, but in the last year, they unloaded all their stars, from Adam Eaton to Jose Quintana, for prospects. Those kind of abrupt sell-offs have changed the structure of the league and moved dozens more players between teams.

Quintana is an especially representative example, because more pitchers are getting moved than in previous years. Hurler trades reached a nadir in 2013, when only 41.6 percent of traded players were pitchers. Last year, however, that percentage had risen to 52.6 percent, a big swing in only a few years. And although we saw a buildup in bullpen swaps last year, with the Indians grabbing Andrew Miller and the Cubs obtaining Aroldis Chapman, the increase in pitcher trades seems to be evenly divided between starters and relievers. In the new, juiced-ball MLB frontier, it may be that teams put an extra premium on acquiring good pitching.

Trades can sometimes reveal the strategies a team is employing or the type of players they value the most. But just as often, they are mysterious, the outcome of negotiations to which the public is not privy. Whether due to tanking, the wild card, or some other factor, trades are way, way up and more pitchers are switching teams than before. That makes the deadline more exciting than ever, but it’s also just another block of time in MLB’s trade-happy calendar.