This is, of course, the Mortgage Bankers' Association indices of mortgage application activity for the previous week. It actually consists of three indices: the Market Composite Index (which tracks overall mortgage application activity), the Purchase Index (which tracks applications for home purchases) and the Refinance Index (which tracks applications for refinancing of existing mortgages). The figures represent week-over-week change.
Traditionally, this is not considered a huge market mover. It's useful information for trying to predict whether home sales will increase or decrease, and it can be used as a data point for the health of the financial sector (particularly mortgage lenders), but the Street doesn't concern itself all that much with this specific index. As a result, there are no analyst opinions on it that I can find.
So let's delve into some number instead, shall we? For the week ending 5/13, the Composite Index was up 7.8%. This was entirely driven by refinancing (the Refinance Index was up 13.2%), as purchase applications fell for the week (dropping 3.2%). To get the data for the week ending 5/20, we turn to the press release on the MBA website. The Market Composite Index increased 1.1%, driven by both new purchases (the Purchase Index was up 1.5%) and refinance activity (the Refinance Index was up 0.9%).
Refinance activity represented 66.8% of all mortgage applications for the week, and adjustable-rate mortgages represented 5.8% of total applications. The average contract rate for 30-year fixed-rate mortgages increased to 4.69%.
 Remember those?