Treasury yields face a key test at 4.8%, with a sustained move above that level potentially creating "meaningful problems" for other asset classes, according to Matt Maley, chief market strategist at Miller Tabak + Co.

"We remain concerned about the Treasury market…as rising fiscal deficits, massive debt issuance, and heavy corporate borrowing continue to pressure long-term yields... while Treasury Department jawboning has failed to produce the desired decline in rates (at least so far)," Maley said in a note over the weekend.