The long-awaited rebound in the used business aircraft market remains elusive, with a mixed bag of market indicators from first-quarter results, market researcher Amstat says in its latest Market Update Report.

Inventories are down overall from a year ago, which is welcome news for new aircraft manufacturers finding themselves competing with near-new models on the market at lower prices. But prices also continue to shrink overall. Pricing has been problematic in both the new and used markets.

The number of used business jet transactions in the first quarter also inched down 0.2% to 2.3% of the fleet changing hands. This is below the 2.5% in fourth quarter 2011 and even with first quarter 2011 results. The 20-year average is 2.9%.

The light jet market remains sluggish with 2.6% of the fleet changing hands in the first quarter. This actually was even with first quarter 2011 results, but down from 2.8% in the fourth quarter 2011 and the 3.3% 20-year average.

The turboprop niche posted similar results, with first quarter 2012 matching 2011 at 2.2%, but down from 2.6% in the fourth quarter. Turbine helicopters, meanwhile, were down from 1.4% in first and fourth quarter 2011 to 1.3% in the most recent quarter.

“The lower transaction activity in Q1 versus Q4 is typical of what we see. However, the flat performance versus Q1 2011 was disappointing and further evidence that we are in a transitional phase in the market cycle,” says Amstat Executive Vice President Tom Benson.

The inventory of used business jets for sale was up a little from the fourth quarter to 13.8% of the available fleet (from 13.7%), but still down from 14.2% a year ago. The medium-jet inventory marked the largest contraction, from 13.8% a year ago to 12.9% in the most recent quarter. The medium jet inventory stood at 13.2% in the fourth quarter. The inventory is moving toward the 20-year average of 12.2%.

The turboprop inventory continues to improve upon the 20-year average of 11.2%, dropping to 9.9% at the end for the first quarter, down from 11.6% a year ago. Turbine helicopters, meanwhile, are approaching the 20-year average of 6% of the fleet for sale, coming in at 6.1% in the first quarter.

At the same time, however, light and medium jet asking prices are still dropping – down 7% from a year ago. But prices for heavy business jets are stabilizing, down just 0.3%. Asking prices for turboprops and turbine helicopters, meanwhile, have increased over the past year – “which is promising for these market segments,” Amstat says.